Convert triangle-opengl example to 3.3 core

docs/quick.dox

@@ -135,9 +135,14 @@ require a minimum OpenGL version by setting the `GLFW_CONTEXT_VERSION_MAJOR` and
 `GLFW_CONTEXT_VERSION_MINOR` hints _before_ creation.  If the required minimum
 version is not supported on the machine, context (and window) creation fails.
 
+You can select the OpenGL profile by setting the `GLFW_OPENGL_PROFILE` hint.
+This program uses the core profile as that is the only profile macOS supports
+for OpenGL 3.x and 4.x.
+
 @code
-glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
-glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 GLFWwindow* window = glfwCreateWindow(640, 480, "My Title", NULL, NULL);
 if (!window)
 {

examples/triangle-opengl.c

@@ -47,11 +47,11 @@ static const Vertex vertices[3] =
 };
 
 static const char* vertex_shader_text =
-"#version 110\n"
+"#version 330\n"
 "uniform mat4 MVP;\n"
-"attribute vec3 vCol;\n"
+"in vec3 vCol;\n"
-"attribute vec2 vPos;\n"
+"in vec2 vPos;\n"
-"varying vec3 color;\n"
+"out vec3 color;\n"
 "void main()\n"
 "{\n"
 "    gl_Position = MVP * vec4(vPos, 0.0, 1.0);\n"
@@ -59,11 +59,12 @@ static const char* vertex_shader_text =
 "}\n";
 
 static const char* fragment_shader_text =
-"#version 110\n"
+"#version 330\n"
-"varying vec3 color;\n"
+"in vec3 color;\n"
+"out vec4 fragment;\n"
 "void main()\n"
 "{\n"
-"    gl_FragColor = vec4(color, 1.0);\n"
+"    fragment = vec4(color, 1.0);\n"
 "}\n";
 
 static void error_callback(int error, const char* description)
@@ -84,8 +85,9 @@ int main(void)
     if (!glfwInit())
         exit(EXIT_FAILURE);
 
-    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
-    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
     GLFWwindow* window = glfwCreateWindow(640, 480, "OpenGL Triangle", NULL, NULL);
     if (!window)
@@ -124,6 +126,9 @@ int main(void)
     const GLint vpos_location = glGetAttribLocation(program, "vPos");
     const GLint vcol_location = glGetAttribLocation(program, "vCol");
 
+    GLuint vertex_array;
+    glGenVertexArrays(1, &vertex_array);
+    glBindVertexArray(vertex_array);
     glEnableVertexAttribArray(vpos_location);
     glVertexAttribPointer(vpos_location, 2, GL_FLOAT, GL_FALSE,
                           sizeof(Vertex), (void*) offsetof(Vertex, pos));
@@ -148,6 +153,7 @@ int main(void)
 
         glUseProgram(program);
         glUniformMatrix4fv(mvp_location, 1, GL_FALSE, (const GLfloat*) mvp);
+        glBindVertexArray(vertex_array);
         glDrawArrays(GL_TRIANGLES, 0, 3);
 
         glfwSwapBuffers(window);