Add OpenGL ES 2.0 triangle example

examples/CMakeLists.txt

@@ -19,6 +19,7 @@ elseif (APPLE)
 endif()
 
 set(GLAD_GL "${GLFW_SOURCE_DIR}/deps/glad/gl.h")
+set(GLAD_GLES2 "${GLFW_SOURCE_DIR}/deps/glad/gles2.h")
 set(GETOPT "${GLFW_SOURCE_DIR}/deps/getopt.h"
            "${GLFW_SOURCE_DIR}/deps/getopt.c")
 set(TINYCTHREAD "${GLFW_SOURCE_DIR}/deps/tinycthread.h"
@@ -32,6 +33,7 @@ add_executable(particles WIN32 MACOSX_BUNDLE particles.c ${ICON} ${TINYCTHREAD}
 add_executable(sharing WIN32 MACOSX_BUNDLE sharing.c ${ICON} ${GLAD_GL})
 add_executable(splitview WIN32 MACOSX_BUNDLE splitview.c ${ICON} ${GLAD_GL})
 add_executable(triangle-opengl WIN32 MACOSX_BUNDLE triangle-opengl.c ${ICON} ${GLAD_GL})
+add_executable(triangle-opengles WIN32 MACOSX_BUNDLE triangle-opengles.c ${ICON} ${GLAD_GLES2})
 add_executable(wave WIN32 MACOSX_BUNDLE wave.c ${ICON} ${GLAD_GL})
 add_executable(windows WIN32 MACOSX_BUNDLE windows.c ${ICON} ${GLAD_GL})
 
@@ -41,7 +43,7 @@ if (RT_LIBRARY)
 endif()
 
 set(GUI_ONLY_BINARIES boing gears heightmap particles sharing splitview
-    triangle-opengl wave windows)
+    triangle-opengl triangle-opengles wave windows)
 set(CONSOLE_BINARIES offscreen)
 
 set_target_properties(${GUI_ONLY_BINARIES} ${CONSOLE_BINARIES} PROPERTIES
@@ -70,6 +72,7 @@ if (APPLE)
     set_target_properties(particles PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "Particles")
     set_target_properties(sharing PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "Sharing")
     set_target_properties(triangle-opengl PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "OpenGL Triangle")
+    set_target_properties(triangle-opengles PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "OpenGL ES Triangle")
     set_target_properties(splitview PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "SplitView")
     set_target_properties(wave PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "Wave")
     set_target_properties(windows PROPERTIES MACOSX_BUNDLE_BUNDLE_NAME "Windows")

examples/triangle-opengles.c

@@ -0,0 +1,170 @@
+//========================================================================
+// OpenGL ES 2.0 triangle example
+// Copyright (c) Camilla Löwy <elmindreda@glfw.org>
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would
+//    be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not
+//    be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source
+//    distribution.
+//
+//========================================================================
+
+#define GLAD_GLES2_IMPLEMENTATION
+#include <glad/gles2.h>
+#define GLFW_INCLUDE_NONE
+#include <GLFW/glfw3.h>
+
+#include "linmath.h"
+
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+
+typedef struct Vertex
+{
+    vec2 pos;
+    vec3 col;
+} Vertex;
+
+static const Vertex vertices[3] =
+{
+    { { -0.6f, -0.4f }, { 1.f, 0.f, 0.f } },
+    { {  0.6f, -0.4f }, { 0.f, 1.f, 0.f } },
+    { {   0.f,  0.6f }, { 0.f, 0.f, 1.f } }
+};
+
+static const char* vertex_shader_text =
+"#version 100\n"
+"precision mediump float;\n"
+"uniform mat4 MVP;\n"
+"attribute vec3 vCol;\n"
+"attribute vec2 vPos;\n"
+"varying vec3 color;\n"
+"void main()\n"
+"{\n"
+"    gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n"
+"    color = vCol;\n"
+"}\n";
+
+static const char* fragment_shader_text =
+"#version 100\n"
+"precision mediump float;\n"
+"varying vec3 color;\n"
+"void main()\n"
+"{\n"
+"    gl_FragColor = vec4(color, 1.0);\n"
+"}\n";
+
+static void error_callback(int error, const char* description)
+{
+    fprintf(stderr, "GLFW Error: %s\n", description);
+}
+
+static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
+{
+    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, GLFW_TRUE);
+}
+
+int main(void)
+{
+    glfwSetErrorCallback(error_callback);
+
+    if (!glfwInit())
+        exit(EXIT_FAILURE);
+
+    glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+    glfwWindowHint(GLFW_CONTEXT_CREATION_API, GLFW_EGL_CONTEXT_API);
+
+    GLFWwindow* window = glfwCreateWindow(640, 480, "OpenGL ES 2.0 Triangle (EGL)", NULL, NULL);
+    if (!window)
+    {
+        glfwWindowHint(GLFW_CONTEXT_CREATION_API, GLFW_NATIVE_CONTEXT_API);
+        window = glfwCreateWindow(640, 480, "OpenGL ES 2.0 Triangle", NULL, NULL);
+        if (!window)
+        {
+            glfwTerminate();
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    glfwSetKeyCallback(window, key_callback);
+
+    glfwMakeContextCurrent(window);
+    gladLoadGLES2(glfwGetProcAddress);
+    glfwSwapInterval(1);
+
+    GLuint vertex_buffer;
+    glGenBuffers(1, &vertex_buffer);
+    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    const GLuint vertex_shader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertex_shader, 1, &vertex_shader_text, NULL);
+    glCompileShader(vertex_shader);
+
+    const GLuint fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragment_shader, 1, &fragment_shader_text, NULL);
+    glCompileShader(fragment_shader);
+
+    const GLuint program = glCreateProgram();
+    glAttachShader(program, vertex_shader);
+    glAttachShader(program, fragment_shader);
+    glLinkProgram(program);
+
+    const GLint mvp_location = glGetUniformLocation(program, "MVP");
+    const GLint vpos_location = glGetAttribLocation(program, "vPos");
+    const GLint vcol_location = glGetAttribLocation(program, "vCol");
+
+    glEnableVertexAttribArray(vpos_location);
+    glEnableVertexAttribArray(vcol_location);
+    glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE,
+                          sizeof(Vertex), (void*) offsetof(Vertex, pos));
+    glVertexAttribPointer(vcol_location, 3, GL_FLOAT, GL_FALSE,
+                          sizeof(Vertex), (void*) offsetof(Vertex, col));
+
+    while (!glfwWindowShouldClose(window))
+    {
+        int width, height;
+        glfwGetFramebufferSize(window, &width, &height);
+        const float ratio = width / (float) height;
+
+        glViewport(0, 0, width, height);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        mat4x4 m, p, mvp;
+        mat4x4_identity(m);
+        mat4x4_rotate_Z(m, m, (float) glfwGetTime());
+        mat4x4_ortho(p, -ratio, ratio, -1.f, 1.f, 1.f, -1.f);
+        mat4x4_mul(mvp, p, m);
+
+        glUseProgram(program);
+        glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) &mvp);
+        glDrawArrays(GL_TRIANGLES, 0, 3);
+
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    glfwDestroyWindow(window);
+
+    glfwTerminate();
+    exit(EXIT_SUCCESS);
+}
+