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Add OpenGL ES variant of Boing demo.
This commit is contained in:
Mike Gorchak
parent
b35641f4a3
commit
098a8c1697
775
examples/boing-opengles.c
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775
examples/boing-opengles.c
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/*****************************************************************************
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* Title: OpenGL ES Boing
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* Desc: Tribute to Amiga Boing.
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* Author: Jim Brooks <gfx@jimbrooks.org>
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* Original Amiga authors were R.J. Mical and Dale Luck.
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* GLFW conversion by Marcus Geelnard
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* OpenGL ES port by Mike Gorchak
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* Notes: - 360' = 2*PI [radian]
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*
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* - Distances between objects are created by doing a relative
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* Z translations.
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*
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* - Although OpenGL ES enticingly supports alpha-blending,
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* the shadow of the original Boing didn't affect the color
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* of the grid.
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*
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* - [Marcus] Changed timing scheme from interval driven to frame-
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* time based animation steps (which results in much smoother
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* movement)
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*
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* History of Amiga Boing:
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*
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* Boing was demonstrated on the prototype Amiga (codenamed "Lorraine") in
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* 1985. According to legend, it was written ad-hoc in one night by
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* R. J. Mical and Dale Luck. Because the bouncing ball animation was so fast
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* and smooth, attendees did not believe the Amiga prototype was really doing
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* the rendering. Suspecting a trick, they began looking around the booth for
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* a hidden computer or VCR.
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*****************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <math.h>
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#define GLAD_GLES2_IMPLEMENTATION
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#include <glad/gles2.h>
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#define GLFW_INCLUDE_NONE
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#include <GLFW/glfw3.h>
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#include <linmath.h>
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/*****************************************************************************
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* Various declarations and macros
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*****************************************************************************/
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/* Draw ball, or its shadow */
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typedef enum
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{
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DRAW_BALL,
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DRAW_BALL_SHADOW
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} DRAW_BALL_ENUM;
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/* Prototypes */
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void init(void);
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void display(void);
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void reshape(GLFWwindow* window, int w, int h);
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void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
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void mouse_button_callback(GLFWwindow* window, int button, int action, int mods);
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void cursor_position_callback(GLFWwindow* window, double x, double y);
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void GenerateBoingBall(void);
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void GenerateGrid(void);
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void DrawBoingBall(DRAW_BALL_ENUM drawBallHow);
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void DrawGrid(void);
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void BounceBall(float dt);
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#define RADIUS 70.0f
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#define STEP_LONGITUDE 22.5f /* 22.5 makes 8 bands like original Boing */
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#define STEP_LATITUDE 22.5f
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#define DIST_BALL (RADIUS * 2.0f + RADIUS * 0.1f)
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#define VIEW_SCENE_DIST (DIST_BALL * 3.0f + 200.0f) /* distance from viewer to middle of boing area */
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#define GRID_SIZE (RADIUS * 4.5f) /* length (width) of grid */
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#define BOUNCE_HEIGHT (RADIUS * 2.1f)
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#define BOUNCE_WIDTH (RADIUS * 2.1f)
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#define SHADOW_OFFSET_X -20.0f
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#define SHADOW_OFFSET_Y 10.f
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#define SHADOW_OFFSET_Z 0.0f
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#define WALL_L_OFFSET 0.0f
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#define WALL_R_OFFSET 5.0f
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/* Animation speed (50.0 mimics the original GLUT demo speed) */
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#define ANIMATION_SPEED 50.0f
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/* Maximum allowed delta time per physics iteration */
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#define MAX_DELTA_T 0.02f
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/* Global vars */
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int windowed_xpos, windowed_ypos, windowed_width, windowed_height;
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int width, height;
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int override_pos = GLFW_FALSE;
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float deg_rot_y = 0.0f;
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float deg_rot_y_inc = 2.0f;
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float cursor_x = 0.0f;
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float cursor_y = 0.0f;
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float ball_x = -RADIUS;
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float ball_y = -RADIUS;
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float ball_x_inc = 1.0f;
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float ball_y_inc = 2.0f;
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float t;
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float t_old = 0.0f;
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float dt;
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/* Random number generator */
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#ifndef RAND_MAX
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#define RAND_MAX 4095
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#endif
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static mat4x4 projection;
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static mat4x4 modelview_orig;
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static mat4x4 modelview;
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static mat4x4 mvp;
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static vec3* ball_color1_vertices = NULL;
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static vec3* ball_color2_vertices = NULL;
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static vec3* grid_vertices = NULL;
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static vec3 color1 = {0.8f, 0.1f, 0.1f}; /* reddish */
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static vec3 color2 = {0.95f, 0.95f, 0.95f}; /* almost white */
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static vec3 color_shadow = {0.35f, 0.35f, 0.35f}; /* dark grey */
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static vec3 grid_color = {0.6f, 0.1f, 0.6f}; /* purple */
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static int facet_array_size = 0;
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static int grid_array_size = 0;
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static GLuint buffer;
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static GLuint program;
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static GLuint mvp_matrix_loc = -1;
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static GLuint vertex_color_loc = -1;
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static GLuint vertex_attr_index = -1;
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/*****************************************************************************
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* Truncate a degree.
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*****************************************************************************/
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float TruncateDeg(float deg)
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{
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if (deg >= 360.0f)
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return (deg - 360.0f);
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else
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return deg;
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}
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/*****************************************************************************
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* Convert a degree (360-based) into a radian.
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* 360' = 2 * PI
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*****************************************************************************/
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float deg2rad(float deg)
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{
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return deg / 360.0f * (2.0f * M_PI);
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}
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/*****************************************************************************
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* 360' sin().
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*****************************************************************************/
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float sin_deg(float deg)
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{
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return sin(deg2rad(deg));
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}
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/*****************************************************************************
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* 360' cos().
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*****************************************************************************/
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float cos_deg(float deg)
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{
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return cos(deg2rad(deg));
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}
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/*****************************************************************************
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* init_shaders()
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*****************************************************************************/
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static int init_shaders(void)
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{
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GLenum error;
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GLuint vertex_shader, fragment_shader;
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char log[8192];
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GLsizei len;
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GLint processing_done = GL_TRUE;
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error = glGetError();
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const char *vtx_shdr_src =
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"attribute vec3 vertex_position; \n"
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" \n"
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"uniform mat4 mvp_matrix; \n"
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"uniform vec4 vertex_color; \n"
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" \n"
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"varying vec4 fs_color; \n"
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" \n"
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"void main() \n"
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"{ \n"
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" fs_color = vertex_color; \n"
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" gl_Position = mvp_matrix * vec4(vertex_position, 1.0); \n"
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"} \n";
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const char *frg_shdr_src =
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"varying vec4 fs_color; \n"
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" \n"
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"void main(void) \n"
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"{ \n"
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" gl_FragColor = fs_color; \n"
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"} \n";
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program = glCreateProgram();
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vertex_shader = glCreateShader(GL_VERTEX_SHADER);
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glAttachShader(program, vertex_shader);
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glShaderSource(vertex_shader, 1, (const char**)&vtx_shdr_src, NULL);
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glCompileShader(vertex_shader);
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glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &processing_done);
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if (processing_done != GL_TRUE)
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{
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glGetShaderInfoLog(vertex_shader, sizeof(log), &len, log);
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fprintf(stderr, "Vertex Shader: %s", log);
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return -1;
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}
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fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
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glAttachShader(program, fragment_shader);
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glShaderSource(fragment_shader, 1, (const char**)&frg_shdr_src, NULL);
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glCompileShader(fragment_shader);
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glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &processing_done);
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if (processing_done != GL_TRUE)
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{
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glGetShaderInfoLog(fragment_shader, sizeof(log), &len, log);
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fprintf(stderr, "Fragment Shader: %s", log);
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return -1;
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}
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glLinkProgram(program);
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glGetProgramiv(program, GL_LINK_STATUS, &processing_done);
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if (processing_done != GL_TRUE)
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{
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glGetProgramInfoLog(program, sizeof(log), &len, log);
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fprintf(stderr, "Linker: %s", log);
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return -1;
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}
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glUseProgram(program);
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mvp_matrix_loc = glGetUniformLocation(program, "mvp_matrix");
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if ((mvp_matrix_loc == -1))
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{
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fprintf(stderr, "Can't locate location of MVP matrix uniform!\n");
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return -1;
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}
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vertex_color_loc = glGetUniformLocation(program, "vertex_color");
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if (vertex_color_loc == -1)
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{
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fprintf(stderr, "Can't locate location of fog color uniform!\n");
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return -1;
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}
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vertex_attr_index = glGetAttribLocation(program, "vertex_position");
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if (vertex_attr_index == -1)
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{
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fprintf(stderr, "Can't locate location of vertex attribute!\n");
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return -1;
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}
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/* We do not change VBO and use index offsets to the array elements */
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glEnableVertexAttribArray(vertex_attr_index);
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glVertexAttribPointer(vertex_attr_index, 3, GL_FLOAT, GL_FALSE, 0, (const GLvoid*)(uintptr_t)0);
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error = glGetError();
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if (error != GL_NO_ERROR)
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{
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fprintf(stderr, "GL Error: 0x%04X in shaders setup\n", error);
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return -1;
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}
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return 0;
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}
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/*****************************************************************************
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* init()
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*****************************************************************************/
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void init(void)
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{
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int offset = 0;
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/* Clear background. */
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glClearColor(0.55f, 0.55f, 0.55f, 0.0f);
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/* Generate initial modelview matrix */
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vec3 eye = {0.0f, 0.0f, VIEW_SCENE_DIST};
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vec3 center = {0.0f, 0.0f, 0.0f};
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vec3 up = {0.0f, -1.0f, 0.0f};
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mat4x4_look_at(modelview_orig, eye, center, up);
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GenerateBoingBall();
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GenerateGrid();
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/* Setup VBO */
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glGenBuffers(1, &buffer);
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glBindBuffer(GL_ARRAY_BUFFER, buffer);
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glBufferData(GL_ARRAY_BUFFER, facet_array_size + facet_array_size + grid_array_size,
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NULL, GL_STATIC_DRAW);
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glBufferSubData(GL_ARRAY_BUFFER, offset, facet_array_size, ball_color1_vertices);
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offset += facet_array_size;
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glBufferSubData(GL_ARRAY_BUFFER, offset, facet_array_size, ball_color2_vertices);
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offset += facet_array_size;
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glBufferSubData(GL_ARRAY_BUFFER, offset, grid_array_size, grid_vertices);
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offset += grid_array_size;
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/* We don't need vertices in a heap, they were uploaded as VBO */
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free(ball_color1_vertices);
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free(ball_color2_vertices);
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free(grid_vertices);
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init_shaders();
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}
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/*****************************************************************************
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* display()
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*****************************************************************************/
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void display(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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DrawBoingBall(DRAW_BALL_SHADOW);
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DrawGrid();
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DrawBoingBall(DRAW_BALL);
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}
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/*****************************************************************************
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* reshape()
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*****************************************************************************/
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void reshape(GLFWwindow* window, int w, int h)
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{
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width = w;
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height = h;
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glViewport(0, 0, (GLsizei)w, (GLsizei)h);
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mat4x4_perspective(projection, 2.0f * (float)atan2(RADIUS, 200.0f), (float)w / (float)h, 1.0f, VIEW_SCENE_DIST);
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}
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void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
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{
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if (action != GLFW_PRESS)
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return;
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if (key == GLFW_KEY_ESCAPE && mods == 0)
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glfwSetWindowShouldClose(window, GLFW_TRUE);
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if ((key == GLFW_KEY_ENTER && mods == GLFW_MOD_ALT) ||
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(key == GLFW_KEY_F11 && mods == GLFW_MOD_ALT))
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{
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if (glfwGetWindowMonitor(window))
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{
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glfwSetWindowMonitor(window, NULL,
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windowed_xpos, windowed_ypos,
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windowed_width, windowed_height, 0);
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}
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else
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{
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GLFWmonitor* monitor = glfwGetPrimaryMonitor();
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if (monitor)
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{
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const GLFWvidmode* mode = glfwGetVideoMode(monitor);
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glfwGetWindowPos(window, &windowed_xpos, &windowed_ypos);
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glfwGetWindowSize(window, &windowed_width, &windowed_height);
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glfwSetWindowMonitor(window, monitor, 0, 0, mode->width, mode->height, mode->refreshRate);
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}
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}
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}
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}
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static void set_ball_pos(float x, float y)
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{
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ball_x = (width / 2) - x;
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ball_y = y - (height / 2);
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}
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void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
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{
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if (button != GLFW_MOUSE_BUTTON_LEFT)
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return;
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if (action == GLFW_PRESS)
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{
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override_pos = GLFW_TRUE;
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set_ball_pos(cursor_x, cursor_y);
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}
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else
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{
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override_pos = GLFW_FALSE;
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}
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}
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void cursor_position_callback(GLFWwindow* window, double x, double y)
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{
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cursor_x = (float)x;
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cursor_y = (float)y;
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if (override_pos)
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set_ball_pos(cursor_x, cursor_y);
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}
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/*****************************************************************************
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* Generate the Boing ball.
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*
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* The Boing ball is sphere in which each facet is a rectangle.
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* Facet colors alternate between red and white.
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* The ball is built by stacking latitudinal circles. Each circle is composed
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* of a widely-separated set of points, so that each facet is noticeably large.
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*****************************************************************************/
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void GenerateBoingBall(void)
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{
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/* degree of longitude */
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float lon_deg;
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float lat_deg;
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int vertex_idx_c1 = 0;
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int vertex_idx_c2 = 0;
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bool colorToggle = 0;
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/* "ne" means south-east, so on */
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vec3 vert_ne;
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vec3 vert_nw;
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vec3 vert_sw;
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vec3 vert_se;
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/* "/ 2" - half facets of one color */
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/* "* 6" - 6 vertices per facet (two triangles) */
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facet_array_size = (int)((180.0f / STEP_LONGITUDE) * (360.0f / STEP_LATITUDE) / 2) * 6 * sizeof(vec3);
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ball_color1_vertices = calloc(1, facet_array_size);
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ball_color2_vertices = calloc(1, facet_array_size);
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if ((ball_color1_vertices == NULL) || (ball_color2_vertices == NULL))
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{
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fprintf(stderr, "Can't allocate memory for ball vertices!\n");
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glfwTerminate();
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exit(EXIT_FAILURE);
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}
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/*
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* Build a faceted latitude slice of the Boing ball,
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* stepping same-sized vertical bands of the sphere.
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*/
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for (lon_deg = 0; lon_deg < 180; lon_deg += STEP_LONGITUDE)
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{
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/*
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* Iterate through the points of a latitude circle.
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* A latitude circle is a 2D set of X,Z points.
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*/
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for (lat_deg = 0; lat_deg <= (360 - STEP_LATITUDE); lat_deg += STEP_LATITUDE)
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{
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/* Assign each Y. */
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vert_ne[1] = vert_nw[1] = (float) cos_deg((lon_deg + STEP_LONGITUDE)) * RADIUS;
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vert_sw[1] = vert_se[1] = (float) cos_deg(lon_deg) * RADIUS;
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/*
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* Assign each X,Z with sin,cos values scaled by latitude radius indexed by longitude.
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* Eg, long=0 and long=180 are at the poles, so zero scale is sin(longitude),
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* while long=90 (sin(90)=1) is at equator.
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*/
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vert_ne[0] = (float)cos_deg(lat_deg ) * (RADIUS * (float)sin_deg(lon_deg + STEP_LONGITUDE));
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vert_se[0] = (float)cos_deg(lat_deg ) * (RADIUS * (float)sin_deg(lon_deg ));
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vert_nw[0] = (float)cos_deg(lat_deg + STEP_LATITUDE) * (RADIUS * (float)sin_deg(lon_deg + STEP_LONGITUDE));
|
||||
vert_sw[0] = (float)cos_deg(lat_deg + STEP_LATITUDE) * (RADIUS * (float)sin_deg(lon_deg ));
|
||||
|
||||
vert_ne[2] = (float)sin_deg(lat_deg ) * (RADIUS * (float)sin_deg(lon_deg + STEP_LONGITUDE));
|
||||
vert_se[2] = (float)sin_deg(lat_deg ) * (RADIUS * (float)sin_deg(lon_deg ));
|
||||
vert_nw[2] = (float)sin_deg(lat_deg + STEP_LATITUDE) * (RADIUS * (float)sin_deg(lon_deg + STEP_LONGITUDE));
|
||||
vert_sw[2] = (float)sin_deg(lat_deg + STEP_LATITUDE) * (RADIUS * (float)sin_deg(lon_deg ));
|
||||
|
||||
/*
|
||||
* Color this polygon with red or white. Replace polygons with
|
||||
* triangles to perform a batch draw operation.
|
||||
*/
|
||||
if (colorToggle)
|
||||
{
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 0], vert_ne, sizeof(vec3)); /* V0 */
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 1], vert_nw, sizeof(vec3)); /* V1 */
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 2], vert_sw, sizeof(vec3)); /* V2 */
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 3], vert_ne, sizeof(vec3)); /* V0 */
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 4], vert_sw, sizeof(vec3)); /* V2 */
|
||||
memcpy(ball_color1_vertices[vertex_idx_c1 + 5], vert_se, sizeof(vec3)); /* V3 */
|
||||
vertex_idx_c1 += 6;
|
||||
}
|
||||
else
|
||||
{
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 0], vert_ne, sizeof(vec3)); /* V0 */
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 1], vert_nw, sizeof(vec3)); /* V1 */
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 2], vert_sw, sizeof(vec3)); /* V2 */
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 3], vert_ne, sizeof(vec3)); /* V0 */
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 4], vert_sw, sizeof(vec3)); /* V2 */
|
||||
memcpy(ball_color2_vertices[vertex_idx_c2 + 5], vert_se, sizeof(vec3)); /* V3 */
|
||||
vertex_idx_c2 += 6;
|
||||
}
|
||||
|
||||
colorToggle = ! colorToggle;
|
||||
}
|
||||
|
||||
/* Toggle color so that next band will opposite red/white colors than this one. */
|
||||
colorToggle = ! colorToggle;
|
||||
}
|
||||
}
|
||||
|
||||
/*****************************************************************************
|
||||
* Bounce the ball.
|
||||
*****************************************************************************/
|
||||
void BounceBall(float delta_t)
|
||||
{
|
||||
float sign;
|
||||
float deg;
|
||||
|
||||
if (override_pos)
|
||||
return;
|
||||
|
||||
/* Bounce on walls */
|
||||
if (ball_x > (BOUNCE_WIDTH / 2 + WALL_R_OFFSET))
|
||||
{
|
||||
ball_x_inc = -0.5f - 0.75f * (float)rand() / (float)RAND_MAX;
|
||||
deg_rot_y_inc = -deg_rot_y_inc;
|
||||
}
|
||||
if (ball_x < -(BOUNCE_HEIGHT / 2 + WALL_L_OFFSET))
|
||||
{
|
||||
ball_x_inc = 0.5f + 0.75f * (float)rand() / (float)RAND_MAX;
|
||||
deg_rot_y_inc = -deg_rot_y_inc;
|
||||
}
|
||||
|
||||
/* Bounce on floor / roof */
|
||||
if (ball_y > BOUNCE_HEIGHT / 2)
|
||||
{
|
||||
ball_y_inc = -0.75f - 1.0f * (float)rand() / (float)RAND_MAX;
|
||||
}
|
||||
if (ball_y < -BOUNCE_HEIGHT / 2 * 0.85)
|
||||
{
|
||||
ball_y_inc = 0.75f + 1.0f * (float)rand() / (float)RAND_MAX;
|
||||
}
|
||||
|
||||
/* Update ball position */
|
||||
ball_x += ball_x_inc * ((float)delta_t * ANIMATION_SPEED);
|
||||
ball_y += ball_y_inc * ((float)delta_t * ANIMATION_SPEED);
|
||||
|
||||
/* Simulate the effects of gravity on Y movement. */
|
||||
if (ball_y_inc < 0) sign = -1.0; else sign = 1.0;
|
||||
|
||||
deg = (ball_y + BOUNCE_HEIGHT / 2) * 90 / BOUNCE_HEIGHT;
|
||||
if (deg > 80) deg = 80;
|
||||
if (deg < 10) deg = 10;
|
||||
|
||||
ball_y_inc = sign * 4.0f * (float)sin_deg(deg);
|
||||
}
|
||||
|
||||
/*****************************************************************************
|
||||
* Draw the ball.
|
||||
*****************************************************************************/
|
||||
void DrawBoingBall(DRAW_BALL_ENUM drawBallHow)
|
||||
{
|
||||
float dt_total, dt2;
|
||||
GLenum error;
|
||||
|
||||
/* Reset error */
|
||||
error = glGetError();
|
||||
|
||||
memcpy(modelview, modelview_orig, sizeof(modelview));
|
||||
|
||||
/* Another relative Z translation to separate objects. */
|
||||
mat4x4_translate_in_place(modelview, 0.0f, 0.0f, DIST_BALL);
|
||||
|
||||
/* Update ball position and rotation (iterate if necessary) */
|
||||
dt_total = dt;
|
||||
while (dt_total > 0.0)
|
||||
{
|
||||
dt2 = dt_total > MAX_DELTA_T ? MAX_DELTA_T : dt_total;
|
||||
dt_total -= dt2;
|
||||
BounceBall(dt2);
|
||||
deg_rot_y = TruncateDeg(deg_rot_y + deg_rot_y_inc * ((float)dt2 * ANIMATION_SPEED));
|
||||
}
|
||||
|
||||
/* Set ball position */
|
||||
mat4x4_translate_in_place(modelview, ball_x, ball_y, 0.0f);
|
||||
|
||||
/* Offset the shadow. */
|
||||
if (drawBallHow == DRAW_BALL_SHADOW)
|
||||
{
|
||||
mat4x4_translate_in_place(modelview, SHADOW_OFFSET_X, SHADOW_OFFSET_Y, SHADOW_OFFSET_Z);
|
||||
}
|
||||
|
||||
/* Tilt the ball. */
|
||||
mat4x4_rotate(modelview, modelview, 0.0f, 0.0f, 1.0f, deg2rad(-20.0f));
|
||||
|
||||
/* Continually rotate ball around Y axis. */
|
||||
mat4x4_rotate(modelview, modelview, 0.0f, 1.0f, 0.0f, deg2rad(deg_rot_y));
|
||||
|
||||
/* Set OpenGL state for Boing ball. */
|
||||
glCullFace(GL_FRONT);
|
||||
glEnable(GL_CULL_FACE);
|
||||
|
||||
mat4x4_mul(mvp, projection, modelview);
|
||||
glUniformMatrix4fv(mvp_matrix_loc, 1, GL_FALSE, (GLfloat*)mvp);
|
||||
|
||||
if (drawBallHow == DRAW_BALL_SHADOW)
|
||||
{
|
||||
glUniform4fv(vertex_color_loc, 1, color_shadow);
|
||||
}
|
||||
else
|
||||
{
|
||||
glUniform4fv(vertex_color_loc, 1, color1);
|
||||
}
|
||||
|
||||
glDrawArrays(GL_TRIANGLES, 0, facet_array_size / sizeof(vec3));
|
||||
|
||||
if (drawBallHow == DRAW_BALL_SHADOW)
|
||||
{
|
||||
glUniform4fv(vertex_color_loc, 1, color_shadow);
|
||||
}
|
||||
else
|
||||
{
|
||||
glUniform4fv(vertex_color_loc, 1, color2);
|
||||
}
|
||||
|
||||
glDrawArrays(GL_TRIANGLES, facet_array_size / sizeof(vec3), facet_array_size / sizeof(vec3));
|
||||
|
||||
error = glGetError();
|
||||
if (error != GL_NO_ERROR)
|
||||
{
|
||||
fprintf(stderr, "GL Error: 0x%04X in ball draw function\n", error);
|
||||
}
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
/*****************************************************************************
|
||||
* Generate grid of lines
|
||||
*****************************************************************************/
|
||||
void GenerateGrid(void)
|
||||
{
|
||||
const int rowTotal = 12; /* must be divisible by 2 */
|
||||
const int colTotal = rowTotal; /* must be same as rowTotal */
|
||||
const float widthLine = 2.0f; /* should be divisible by 2 */
|
||||
const float sizeCell = GRID_SIZE / rowTotal;
|
||||
const float z_offset = -40.0f;
|
||||
int row, col;
|
||||
float xl, xr;
|
||||
float yt, yb;
|
||||
int grid_idx = 0;
|
||||
|
||||
/* "* 6" - 6 vertices per line (two triangles) */
|
||||
grid_array_size = ((rowTotal + 1) + (colTotal + 1)) * 6 * sizeof(vec3);
|
||||
grid_vertices = calloc(1, facet_array_size);
|
||||
if (grid_vertices == NULL)
|
||||
{
|
||||
fprintf(stderr, "Can't allocate memory for grid vertices!\n");
|
||||
glfwTerminate();
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
/* Generate vertical lines (as skinny 3D rectangles). */
|
||||
for (col = 0; col <= colTotal; col++)
|
||||
{
|
||||
/* Compute coords of line. */
|
||||
xl = -GRID_SIZE / 2 + col * sizeCell;
|
||||
xr = xl + widthLine;
|
||||
|
||||
yt = GRID_SIZE / 2;
|
||||
yb = -GRID_SIZE / 2 - widthLine;
|
||||
|
||||
memcpy(grid_vertices[grid_idx + 0], (vec3){xr, yt, z_offset}, sizeof(vec3)); /* NE, V0 */
|
||||
memcpy(grid_vertices[grid_idx + 1], (vec3){xl, yt, z_offset}, sizeof(vec3)); /* NW, V1 */
|
||||
memcpy(grid_vertices[grid_idx + 2], (vec3){xl, yb, z_offset}, sizeof(vec3)); /* SW, V2 */
|
||||
memcpy(grid_vertices[grid_idx + 3], (vec3){xr, yt, z_offset}, sizeof(vec3)); /* NE, V0 */
|
||||
memcpy(grid_vertices[grid_idx + 4], (vec3){xl, yb, z_offset}, sizeof(vec3)); /* SW, V2 */
|
||||
memcpy(grid_vertices[grid_idx + 5], (vec3){xr, yb, z_offset}, sizeof(vec3)); /* SE, V3 */
|
||||
grid_idx += 6;
|
||||
}
|
||||
|
||||
/* Generate horizontal lines (as skinny 3D rectangles). */
|
||||
for (row = 0; row <= rowTotal; row++)
|
||||
{
|
||||
/* Compute coords of line. */
|
||||
yt = GRID_SIZE / 2 - row * sizeCell;
|
||||
yb = yt - widthLine;
|
||||
|
||||
xl = -GRID_SIZE / 2;
|
||||
xr = GRID_SIZE / 2 + widthLine;
|
||||
|
||||
memcpy(grid_vertices[grid_idx + 0], (vec3){xr, yt, z_offset}, sizeof(vec3)); /* NE, V0 */
|
||||
memcpy(grid_vertices[grid_idx + 1], (vec3){xl, yt, z_offset}, sizeof(vec3)); /* NW, V1 */
|
||||
memcpy(grid_vertices[grid_idx + 2], (vec3){xl, yb, z_offset}, sizeof(vec3)); /* SW, V2 */
|
||||
memcpy(grid_vertices[grid_idx + 3], (vec3){xr, yt, z_offset}, sizeof(vec3)); /* NE, V0 */
|
||||
memcpy(grid_vertices[grid_idx + 4], (vec3){xl, yb, z_offset}, sizeof(vec3)); /* SW, V2 */
|
||||
memcpy(grid_vertices[grid_idx + 5], (vec3){xr, yb, z_offset}, sizeof(vec3)); /* SE, V3 */
|
||||
grid_idx += 6;
|
||||
}
|
||||
}
|
||||
|
||||
/*****************************************************************************
|
||||
* Draw the purple grid of lines, behind the Boing ball.
|
||||
* When the Workbench is dropped to the bottom, Boing shows 12 rows.
|
||||
*****************************************************************************/
|
||||
void DrawGrid(void)
|
||||
{
|
||||
memcpy(modelview, modelview_orig, sizeof(modelview));
|
||||
|
||||
glDisable(GL_CULL_FACE);
|
||||
|
||||
/* Another relative Z translation to separate objects. */
|
||||
mat4x4_translate_in_place(modelview, 0.0f, 0.0f, DIST_BALL);
|
||||
|
||||
mat4x4_mul(mvp, projection, modelview);
|
||||
glUniformMatrix4fv(mvp_matrix_loc, 1, GL_FALSE, (GLfloat*)mvp);
|
||||
|
||||
glUniform4fv(vertex_color_loc, 1, grid_color);
|
||||
glDrawArrays(GL_TRIANGLES, (facet_array_size + facet_array_size) / sizeof(vec3),
|
||||
(facet_array_size + facet_array_size) / sizeof(vec3));
|
||||
|
||||
return;
|
||||
}
|
||||
|
||||
/*======================================================================*
|
||||
* main()
|
||||
*======================================================================*/
|
||||
|
||||
int main(void)
|
||||
{
|
||||
GLFWwindow* window;
|
||||
|
||||
/* Init GLFW */
|
||||
if (!glfwInit())
|
||||
exit(EXIT_FAILURE);
|
||||
|
||||
window = glfwCreateWindow(400, 400, "Boing OpenGL ES 2.x (classic Amiga demo)", NULL, NULL);
|
||||
if (!window)
|
||||
{
|
||||
glfwTerminate();
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
glfwSetWindowAspectRatio(window, 1, 1);
|
||||
|
||||
glfwSetFramebufferSizeCallback(window, reshape);
|
||||
glfwSetKeyCallback(window, key_callback);
|
||||
glfwSetMouseButtonCallback(window, mouse_button_callback);
|
||||
glfwSetCursorPosCallback(window, cursor_position_callback);
|
||||
|
||||
glfwMakeContextCurrent(window);
|
||||
gladLoadGLES2(glfwGetProcAddress);
|
||||
glfwSwapInterval(1);
|
||||
|
||||
glfwGetFramebufferSize(window, &width, &height);
|
||||
reshape(window, width, height);
|
||||
|
||||
glfwSetTime(0.0);
|
||||
|
||||
init();
|
||||
|
||||
/* Main loop */
|
||||
for (;;)
|
||||
{
|
||||
/* Timing */
|
||||
t = glfwGetTime();
|
||||
dt = t - t_old;
|
||||
t_old = t;
|
||||
|
||||
/* Draw one frame */
|
||||
display();
|
||||
|
||||
/* Swap buffers */
|
||||
glfwSwapBuffers(window);
|
||||
glfwPollEvents();
|
||||
|
||||
/* Check if we are still running */
|
||||
if (glfwWindowShouldClose(window))
|
||||
break;
|
||||
}
|
||||
|
||||
glfwTerminate();
|
||||
exit(EXIT_SUCCESS);
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user