+/* extension #defines, types and entries, avoiding a dependency on additional
+ libraries like GLEW or the GL/glext.h header */
+#ifndef GL_ARRAY_BUFFER
+#define GL_ARRAY_BUFFER 0x8892
+#endif
+
+#ifndef GL_STATIC_DRAW
+#define GL_STATIC_DRAW 0x88E4
+#endif
+
+#ifndef GL_FRAGMENT_SHADER
+#define GL_FRAGMENT_SHADER 0x8B30
+#endif
+
+#ifndef GL_VERTEX_SHADER
+#define GL_VERTEX_SHADER 0x8B31
+#endif
+
+#ifndef GL_SHADING_LANGUAGE_VERSION
+#define GL_SHADING_LANGUAGE_VERSION 0x8B8C
+#endif
+
+#ifndef GL_COMPILE_STATUS
+#define GL_COMPILE_STATUS 0x8B81
+#endif
+
+#ifndef GL_LINK_STATUS
+#define GL_LINK_STATUS 0x8B82
+#endif
+
+#ifndef GL_INFO_LOG_LENGTH
+#define GL_INFO_LOG_LENGTH 0x8B84
+#endif
+
+typedef ptrdiff_t ourGLsizeiptr;
+typedef char ourGLchar;
+
+#ifndef APIENTRY
+#define APIENTRY
+#endif
+
+typedef void (APIENTRY *PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers);
+typedef void (APIENTRY *PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer);
+typedef void (APIENTRY *PFNGLBUFFERDATAPROC) (GLenum target, ourGLsizeiptr size, const GLvoid *data, GLenum usage);
+typedef GLuint (APIENTRY *PFNGLCREATESHADERPROC) (GLenum type);
+typedef void (APIENTRY *PFNGLSHADERSOURCEPROC) (GLuint shader, GLsizei count, const ourGLchar **string, const GLint *length);
+typedef void (APIENTRY *PFNGLCOMPILESHADERPROC) (GLuint shader);
+typedef GLuint (APIENTRY *PFNGLCREATEPROGRAMPROC) (void);
+typedef void (APIENTRY *PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader);
+typedef void (APIENTRY *PFNGLLINKPROGRAMPROC) (GLuint program);
+typedef void (APIENTRY *PFNGLUSEPROGRAMPROC) (GLuint program);
+typedef void (APIENTRY *PFNGLGETSHADERIVPROC) (GLuint shader, GLenum pname, GLint *params);
+typedef void (APIENTRY *PFNGLGETSHADERINFOLOGPROC) (GLuint shader, GLsizei bufSize, GLsizei *length, ourGLchar *infoLog);
+typedef void (APIENTRY *PFNGLGETPROGRAMIVPROC) (GLenum target, GLenum pname, GLint *params);
+typedef void (APIENTRY *PFNGLGETPROGRAMINFOLOGPROC) (GLuint program, GLsizei bufSize, GLsizei *length, ourGLchar *infoLog);
+typedef GLint (APIENTRY *PFNGLGETATTRIBLOCATIONPROC) (GLuint program, const ourGLchar *name);
+typedef void (APIENTRY *PFNGLVERTEXATTRIBPOINTERPROC) (GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *pointer);
+typedef void (APIENTRY *PFNGLENABLEVERTEXATTRIBARRAYPROC) (GLuint index);
+typedef GLint (APIENTRY *PFNGLGETUNIFORMLOCATIONPROC) (GLuint program, const ourGLchar *name);
+typedef void (APIENTRY *PFNGLUNIFORMMATRIX4FVPROC) (GLint location, GLsizei count, GLboolean transpose, const GLfloat *value);
+
+PFNGLGENBUFFERSPROC gl_GenBuffers;
+PFNGLBINDBUFFERPROC gl_BindBuffer;
+PFNGLBUFFERDATAPROC gl_BufferData;
+PFNGLCREATESHADERPROC gl_CreateShader;
+PFNGLSHADERSOURCEPROC gl_ShaderSource;
+PFNGLCOMPILESHADERPROC gl_CompileShader;
+PFNGLCREATEPROGRAMPROC gl_CreateProgram;
+PFNGLATTACHSHADERPROC gl_AttachShader;
+PFNGLLINKPROGRAMPROC gl_LinkProgram;
+PFNGLUSEPROGRAMPROC gl_UseProgram;
+PFNGLGETSHADERIVPROC gl_GetShaderiv;
+PFNGLGETSHADERINFOLOGPROC gl_GetShaderInfoLog;
+PFNGLGETPROGRAMIVPROC gl_GetProgramiv;
+PFNGLGETPROGRAMINFOLOGPROC gl_GetProgramInfoLog;
+PFNGLGETATTRIBLOCATIONPROC gl_GetAttribLocation;
+PFNGLVERTEXATTRIBPOINTERPROC gl_VertexAttribPointer;
+PFNGLENABLEVERTEXATTRIBARRAYPROC gl_EnableVertexAttribArray;
+PFNGLGETUNIFORMLOCATIONPROC gl_GetUniformLocation;
+PFNGLUNIFORMMATRIX4FVPROC gl_UniformMatrix4fv;
+
+void initExtensionEntries(void)
+{
+ gl_GenBuffers = (PFNGLGENBUFFERSPROC) glutGetProcAddress ("glGenBuffers");
+ gl_BindBuffer = (PFNGLBINDBUFFERPROC) glutGetProcAddress ("glBindBuffer");
+ gl_BufferData = (PFNGLBUFFERDATAPROC) glutGetProcAddress ("glBufferData");
+ gl_CreateShader = (PFNGLCREATESHADERPROC) glutGetProcAddress ("glCreateShader");
+ gl_ShaderSource = (PFNGLSHADERSOURCEPROC) glutGetProcAddress ("glShaderSource");
+ gl_CompileShader = (PFNGLCOMPILESHADERPROC) glutGetProcAddress ("glCompileShader");
+ gl_CreateProgram = (PFNGLCREATEPROGRAMPROC) glutGetProcAddress ("glCreateProgram");
+ gl_AttachShader = (PFNGLATTACHSHADERPROC) glutGetProcAddress ("glAttachShader");
+ gl_LinkProgram = (PFNGLLINKPROGRAMPROC) glutGetProcAddress ("glLinkProgram");
+ gl_UseProgram = (PFNGLUSEPROGRAMPROC) glutGetProcAddress ("glUseProgram");
+ gl_GetShaderiv = (PFNGLGETSHADERIVPROC) glutGetProcAddress ("glGetShaderiv");
+ gl_GetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC) glutGetProcAddress ("glGetShaderInfoLog");
+ gl_GetProgramiv = (PFNGLGETPROGRAMIVPROC) glutGetProcAddress ("glGetProgramiv");
+ gl_GetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC) glutGetProcAddress ("glGetProgramInfoLog");
+ gl_GetAttribLocation = (PFNGLGETATTRIBLOCATIONPROC) glutGetProcAddress ("glGetAttribLocation");
+ gl_VertexAttribPointer = (PFNGLVERTEXATTRIBPOINTERPROC) glutGetProcAddress ("glVertexAttribPointer");
+ gl_EnableVertexAttribArray = (PFNGLENABLEVERTEXATTRIBARRAYPROC) glutGetProcAddress ("glEnableVertexAttribArray");
+ gl_GetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC) glutGetProcAddress ("glGetUniformLocation");
+ gl_UniformMatrix4fv = (PFNGLUNIFORMMATRIX4FVPROC) glutGetProcAddress ("glUniformMatrix4fv");
+}
+
+/* vertex array data for a colored 2D triangle, consisting of RGB color values
+ and XY coordinates */
+const GLfloat varray[] = {
+ 1.0f, 0.0f, 0.0f, /* red */
+ 5.0f, 5.0f, /* lower left */
+
+ 0.0f, 1.0f, 0.0f, /* green */
+ 25.0f, 5.0f, /* lower right */
+
+ 0.0f, 0.0f, 1.0f, /* blue */
+ 5.0f, 25.0f /* upper left */
+};
+
+/* ISO C somehow enforces this silly use of 'enum' for compile-time constants */
+enum {
+ numColorComponents = 3,
+ numVertexComponents = 2,
+ stride = sizeof(GLfloat) * (numColorComponents + numVertexComponents),
+ numElements = sizeof(varray) / stride
+};
+
+/* the name of the vertex buffer object */
+GLuint vertexBufferName;
+
+void initBuffer(void)
+{
+ gl_GenBuffers (1, &vertexBufferName);
+ gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName);
+ gl_BufferData (GL_ARRAY_BUFFER, sizeof(varray), varray, GL_STATIC_DRAW);
+ checkError ("initBuffer");
+}
+
+const ourGLchar *vertexShaderSource[] = {
+ "#version 140\n",
+ "uniform mat4 fg_ProjectionMatrix;\n",
+ "in vec4 fg_Color;\n",
+ "in vec4 fg_Vertex;\n",
+ "smooth out vec4 fg_SmoothColor;\n",
+ "void main()\n",
+ "{\n",
+ " fg_SmoothColor = fg_Color;\n",
+ " gl_Position = fg_ProjectionMatrix * fg_Vertex;\n",
+ "}\n"
+};
+
+const ourGLchar *fragmentShaderSource[] = {
+ "#version 140\n",
+ "smooth in vec4 fg_SmoothColor;\n",
+ "out vec4 fg_FragColor;\n",
+ "void main(void)\n",
+ "{\n",
+ " fg_FragColor = fg_SmoothColor;\n",
+ "}\n"
+};
+
+void compileAndCheck(GLuint shader)
+{
+ GLint status;
+ gl_CompileShader (shader);
+ gl_GetShaderiv (shader, GL_COMPILE_STATUS, &status);
+ if (status == GL_FALSE) {
+ GLint infoLogLength;
+ ourGLchar *infoLog;
+ gl_GetShaderiv (shader, GL_INFO_LOG_LENGTH, &infoLogLength);
+ infoLog = (ourGLchar*) malloc (infoLogLength);
+ gl_GetShaderInfoLog (shader, infoLogLength, NULL, infoLog);
+ fprintf (stderr, "compile log: %s\n", infoLog);
+ free (infoLog);
+ }
+}
+
+GLuint compileShaderSource(GLenum type, GLsizei count, const ourGLchar **string)
+{
+ GLuint shader = gl_CreateShader (type);
+ gl_ShaderSource (shader, count, string, NULL);
+ compileAndCheck (shader);
+ return shader;
+}
+
+void linkAndCheck(GLuint program)
+{
+ GLint status;
+ gl_LinkProgram (program);
+ gl_GetProgramiv (program, GL_LINK_STATUS, &status);
+ if (status == GL_FALSE) {
+ GLint infoLogLength;
+ ourGLchar *infoLog;
+ gl_GetProgramiv (program, GL_INFO_LOG_LENGTH, &infoLogLength);
+ infoLog = (ourGLchar*) malloc (infoLogLength);
+ gl_GetProgramInfoLog (program, infoLogLength, NULL, infoLog);
+ fprintf (stderr, "link log: %s\n", infoLog);
+ free (infoLog);
+ }
+}
+
+GLuint createProgram(GLuint vertexShader, GLuint fragmentShader)
+{
+ GLuint program = gl_CreateProgram ();
+ if (vertexShader != 0) {
+ gl_AttachShader (program, vertexShader);
+ }
+ if (fragmentShader != 0) {
+ gl_AttachShader (program, fragmentShader);
+ }
+ linkAndCheck (program);
+ return program;
+}
+
+GLuint fgProjectionMatrixIndex;
+GLuint fgColorIndex;
+GLuint fgVertexIndex;
+
+void initShader(void)
+{
+ const GLsizei vertexShaderLines = sizeof(vertexShaderSource) / sizeof(ourGLchar*);
+ GLuint vertexShader =
+ compileShaderSource (GL_VERTEX_SHADER, vertexShaderLines, vertexShaderSource);
+
+ const GLsizei fragmentShaderLines = sizeof(fragmentShaderSource) / sizeof(ourGLchar*);
+ GLuint fragmentShader =
+ compileShaderSource (GL_FRAGMENT_SHADER, fragmentShaderLines, fragmentShaderSource);
+
+ GLuint program = createProgram (vertexShader, fragmentShader);
+
+ gl_UseProgram (program);
+
+ fgProjectionMatrixIndex = gl_GetUniformLocation(program, "fg_ProjectionMatrix");
+
+ fgColorIndex = gl_GetAttribLocation(program, "fg_Color");
+ gl_EnableVertexAttribArray (fgColorIndex);
+
+ fgVertexIndex = gl_GetAttribLocation(program, "fg_Vertex");
+ gl_EnableVertexAttribArray (fgVertexIndex);
+
+ checkError ("initShader");
+}
+
+void initRendering(void)