/*
* smooth_opengl3.c, based on smooth.c, which is (c) by SGI, see below.
* This program demonstrates smooth shading in a way which is fully
- * OpenGL-3.0-compliant.
+ * OpenGL-3.1-compliant.
* A smooth shaded polygon is drawn in a 2-D projection.
*/
#include <GL/freeglut.h>
#include <stdlib.h>
#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
/* report GL errors, if any, to stderr */
-void reportErrors(const char *message)
+void checkError(const char *functionName)
{
GLenum error;
while (( error = glGetError() ) != GL_NO_ERROR) {
- fprintf (stderr, "GL error 0x%X %s\n", error, message);
+ fprintf (stderr, "GL error 0x%X detected in %s\n", error, functionName);
}
}
-/* extension entries */
-void (*gl_GenBuffers) (GLsizei n, GLuint *buffers);
-void (*gl_BindBuffer) (GLenum target, GLuint buffer);
-void (*gl_BufferData) (GLenum target, GLsizeiptr size, const GLvoid *data,
- GLenum usage);
+/* 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
-void initExtensionEntries(void)
+#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
+
+
+#ifndef GL_ARB_vertex_array_object
+typedef void (APIENTRY *PFNGLGENVERTEXARRAYSPROC) (GLsizei n, GLuint *arrays);
+typedef void (APIENTRY *PFNGLBINDVERTEXARRAYPROC) (GLuint array);
+#endif
+#ifndef GL_VERSION_1_5
+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);
+#endif
+#ifndef GL_VERSION_2_0
+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);
+#endif
+
+PFNGLGENVERTEXARRAYSPROC gl_GenVertexArrays;
+PFNGLBINDVERTEXARRAYPROC gl_BindVertexArray;
+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 = glutGetProcAddress ("glGenBuffers");
- gl_BindBuffer = glutGetProcAddress ("glBindBuffer");
- gl_BufferData = glutGetProcAddress ("glBufferData");
+ gl_GenVertexArrays = (PFNGLGENVERTEXARRAYSPROC) glutGetProcAddress ("glGenVertexArrays");
+ gl_BindVertexArray = (PFNGLBINDVERTEXARRAYPROC) glutGetProcAddress ("glBindVertexArray");
+ if (!gl_GenVertexArrays || !gl_BindVertexArray)
+ {
+ fprintf (stderr, "glGenVertexArrays or glBindVertexArray not found");
+ exit(1);
+ }
+ gl_GenBuffers = (PFNGLGENBUFFERSPROC) glutGetProcAddress ("glGenBuffers");
+ gl_BindBuffer = (PFNGLBINDBUFFERPROC) glutGetProcAddress ("glBindBuffer");
+ gl_BufferData = (PFNGLBUFFERDATAPROC) glutGetProcAddress ("glBufferData");
+ if (!gl_GenBuffers || !gl_BindBuffer || !gl_BufferData)
+ {
+ fprintf (stderr, "glGenBuffers, glBindBuffer or glBufferData not found");
+ exit(1);
+ }
+ 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");
+ if (!gl_CreateShader || !gl_ShaderSource || !gl_CompileShader || !gl_CreateProgram || !gl_AttachShader || !gl_LinkProgram || !gl_UseProgram || !gl_GetShaderiv || !gl_GetShaderInfoLog || !gl_GetProgramiv || !gl_GetProgramInfoLog || !gl_GetAttribLocation || !gl_VertexAttribPointer || !gl_EnableVertexAttribArray || !gl_GetUniformLocation || !gl_UniformMatrix4fv)
+ {
+ fprintf (stderr, "glCreateShader, glShaderSource, glCompileShader, glCreateProgram, glAttachShader, glLinkProgram, glUseProgram, glGetShaderiv, glGetShaderInfoLog, glGetProgramiv, glGetProgramInfoLog, glGetAttribLocation, glVertexAttribPointer, glEnableVertexAttribArray, glGetUniformLocation or glUniformMatrix4fv not found");
+ exit(1);
+ }
}
/* vertex array data for a colored 2D triangle, consisting of RGB color values
and XY coordinates */
-const GLsizei numColorComponents = 3;
-const GLsizei numVertexComponents = 2;
-
const GLfloat varray[] = {
- 1.0f, 0.0f, 0.0f,
- 5.0f, 5.0f,
+ 1.0f, 0.0f, 0.0f, /* red */
+ 5.0f, 5.0f, /* lower left */
- 0.0f, 1.0f, 0.0f,
- 25.0f, 5.0f,
+ 0.0f, 1.0f, 0.0f, /* green */
+ 25.0f, 5.0f, /* lower right */
- 0.0f, 0.0f, 1.0f,
- 5.0f, 25.0f
+ 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 bufferName;
+GLuint vertexBufferName;
+GLuint vertexArrayName;
void initBuffer(void)
{
- reportErrors ("at start of initBuffer");
- gl_GenBuffers (1, &bufferName);
- gl_BindBuffer (GL_ARRAY_BUFFER, bufferName);
+ /* Need to setup a vertex array as otherwise invalid operation errors can
+ * occur when accessing vertex buffer (OpenGL 3.3 has no default zero named
+ * vertex array)
+ */
+ gl_GenVertexArrays(1, &vertexArrayName);
+ gl_BindVertexArray(vertexArrayName);
+
+ gl_GenBuffers (1, &vertexBufferName);
+ gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName);
gl_BufferData (GL_ARRAY_BUFFER, sizeof(varray), varray, GL_STATIC_DRAW);
- reportErrors ("at end of initBuffer");
+ 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)
{
- reportErrors ("at start of initRendering");
glClearColor (0.0, 0.0, 0.0, 0.0);
- glShadeModel (GL_SMOOTH);
- reportErrors ("at end of initRendering");
+ checkError ("initRendering");
}
void init(void)
{
- initExtensionEntries();
- initBuffer();
- initRendering();
+ initExtensionEntries ();
+ initBuffer ();
+ initShader ();
+ initRendering ();
+}
+
+void dumpInfo(void)
+{
+ printf ("Vendor: %s\n", glGetString (GL_VENDOR));
+ printf ("Renderer: %s\n", glGetString (GL_RENDERER));
+ printf ("Version: %s\n", glGetString (GL_VERSION));
+ printf ("GLSL: %s\n", glGetString (GL_SHADING_LANGUAGE_VERSION));
+ checkError ("dumpInfo");
}
+const GLvoid *bufferObjectPtr (GLsizei index)
+{
+ return (const GLvoid *) (((char *) NULL) + index);
+}
+
+GLfloat projectionMatrix[16];
+
void triangle(void)
{
- const char *base = NULL;
- const GLsizei stride = sizeof(GLfloat) * (numColorComponents + numVertexComponents);
- const GLsizei numElements = sizeof(varray) / stride;
- reportErrors ("at start of triangle");
- gl_BindBuffer (GL_ARRAY_BUFFER, bufferName);
- glColorPointer (numColorComponents, GL_FLOAT, stride, base);
- glVertexPointer(numVertexComponents, GL_FLOAT, stride,
- base + sizeof(GLfloat) * numColorComponents);
- glEnableClientState (GL_COLOR_ARRAY);
- glEnableClientState (GL_VERTEX_ARRAY);
+ gl_UniformMatrix4fv (fgProjectionMatrixIndex, 1, GL_FALSE, projectionMatrix);
+
+ gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName);
+ gl_VertexAttribPointer (fgColorIndex, numColorComponents, GL_FLOAT, GL_FALSE,
+ stride, bufferObjectPtr (0));
+ gl_VertexAttribPointer (fgVertexIndex, numVertexComponents, GL_FLOAT, GL_FALSE,
+ stride, bufferObjectPtr (sizeof(GLfloat) * numColorComponents));
glDrawArrays(GL_TRIANGLES, 0, numElements);
- reportErrors ("at end of triangle");
+ checkError ("triangle");
}
void display(void)
{
- reportErrors ("at start of display");
glClear (GL_COLOR_BUFFER_BIT);
triangle ();
glFlush ();
- reportErrors ("at end of display");
+ checkError ("display");
}
void loadOrthof(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t,
void reshape (int w, int h)
{
- GLfloat m[16];
- reportErrors ("at start of reshape");
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
- glMatrixMode (GL_PROJECTION);
if (w <= h) {
- loadOrtho2Df (m, 0.0, 30.0, 0.0, 30.0 * (GLfloat) h/(GLfloat) w);
+ loadOrtho2Df (projectionMatrix, 0.0f, 30.0f, 0.0f, 30.0f * (GLfloat) h/(GLfloat) w);
} else {
- loadOrtho2Df (m, 0.0, 30.0 * (GLfloat) w/(GLfloat) h, 0.0, 30.0);
+ loadOrtho2Df (projectionMatrix, 0.0f, 30.0f * (GLfloat) w/(GLfloat) h, 0.0f, 30.0f);
}
- glLoadMatrixf (m);
- glMatrixMode (GL_MODELVIEW);
- reportErrors ("at end of reshape");
+ checkError ("reshape");
}
void keyboard(unsigned char key, int x, int y)
}
}
+void samplemenu(int menuID)\r
+{}
+
int main(int argc, char** argv)
{
+ int menuA;
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
- glutInitContextVersion(3, 0);
- /* glutInitContextFlags(GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG); */
+ /* add command line argument "classic" for a pre-3.x context */
+ if ((argc != 2) || (strcmp (argv[1], "classic") != 0)) {
+ glutInitContextVersion (3, 1);
+ glutInitContextFlags (GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG);
+ }
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
+ dumpInfo ();
init ();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc (keyboard);
+
+ /* Add a menu. They have their own context and should thus work with forward compatible main windows too. */
+ menuA = glutCreateMenu(samplemenu);\r
+ glutAddMenuEntry("Sub menu A1 (01)",1);\r
+ glutAddMenuEntry("Sub menu A2 (02)",2);\r
+ glutAddMenuEntry("Sub menu A3 (03)",3);
+ glutSetMenu(menuA);\r
+ glutAttachMenu(GLUT_RIGHT_BUTTON);
+
glutMainLoop();
return 0;
}
projects / freeglut / blobdiff