X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=progs%2Fdemos%2Fsmooth_opengl3%2Fsmooth_opengl3.c;h=358f93b7276979a532b239cba18353178de68a6f;hb=173f90f45d485c259711781edd71ed0eeb073c4f;hp=9a7915f249472bcb7501fd49f75d4e10d678fd23;hpb=b8483fc82178e500314479c6473ff3ae8f3cb3bc;p=freeglut diff --git a/progs/demos/smooth_opengl3/smooth_opengl3.c b/progs/demos/smooth_opengl3/smooth_opengl3.c index 9a7915f..358f93b 100755 --- a/progs/demos/smooth_opengl3/smooth_opengl3.c +++ b/progs/demos/smooth_opengl3/smooth_opengl3.c @@ -45,44 +45,267 @@ #include #include #include +#include -void reportErrors(const char *message) +/* report GL errors, if any, to stderr */ +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); } } -void init(void) +/* extension #defines, types and entries, avoiding a dependency on additional + libraries like GLEW or the GL/glext.h header */ +#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 void (*PFNGLGENBUFFERSPROC) (GLsizei n, GLuint *buffers); +PFNGLGENBUFFERSPROC gl_GenBuffers; + +typedef void (*PFNGLBINDBUFFERPROC) (GLenum target, GLuint buffer); +PFNGLBINDBUFFERPROC gl_BindBuffer; + +typedef void (*PFNGLBUFFERDATAPROC) (GLenum target, GLsizeiptr size, + const GLvoid *data, GLenum usage); +PFNGLBUFFERDATAPROC gl_BufferData; + +typedef GLuint (*PFNGLCREATESHADERPROC) (GLenum type); +PFNGLCREATESHADERPROC gl_CreateShader; + +typedef void (*PFNGLSHADERSOURCEPROC) + (GLuint shader, GLsizei count, const GLchar **string, const GLint *length); +PFNGLSHADERSOURCEPROC gl_ShaderSource; + +typedef void (*PFNGLCOMPILESHADERPROC) (GLuint shader); +PFNGLCOMPILESHADERPROC gl_CompileShader; + +typedef GLuint (*PFNGLCREATEPROGRAMPROC) (void); +PFNGLCREATEPROGRAMPROC gl_CreateProgram; + +typedef void (*PFNGLATTACHSHADERPROC) (GLuint program, GLuint shader); +PFNGLATTACHSHADERPROC gl_AttachShader; + +typedef void (*PFNGLLINKPROGRAMPROC) (GLuint program); +PFNGLLINKPROGRAMPROC gl_LinkProgram; + +typedef void (*PFNGLUSEPROGRAMPROC) (GLuint program); +PFNGLUSEPROGRAMPROC gl_UseProgram; + +typedef void (*PFNGLGETSHADERIVPROC) (GLuint shader, GLenum pname, GLint *params); +PFNGLGETSHADERIVPROC gl_GetShaderiv; + +typedef void (*PFNGLGETSHADERINFOLOGPROC) + (GLuint shader, GLsizei bufSize, GLsizei *length, GLchar *infoLog); +PFNGLGETSHADERINFOLOGPROC gl_GetShaderInfoLog; + +typedef void (*PFNGLGETPROGRAMIVPROC) (GLenum target, GLenum pname, GLint *params); +PFNGLGETPROGRAMIVPROC gl_GetProgramiv; + +typedef void (*PFNGLGETPROGRAMINFOLOGPROC) + (GLuint program, GLsizei bufSize, GLsizei *length, GLchar *infoLog); +PFNGLGETPROGRAMINFOLOGPROC gl_GetProgramInfoLog; + +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"); +} + +/* 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); + glEnableClientState (GL_COLOR_ARRAY); + glEnableClientState (GL_VERTEX_ARRAY); + checkError ("initBuffer"); +} + +const GLchar *vertexShaderSource[] = { + "#version 120\n", + "void main(void)\n", + "{\n", + " gl_FrontColor = gl_Color;\n", + " gl_Position = ftransform();\n", + "}\n" +}; + +const GLchar *fragmentShaderSource[] = { + "#version 120\n", + "void main(void)\n", + "{\n", + " gl_FragColor = gl_Color;\n", + "}\n" +}; + +void compileAndCheck(GLuint shader) +{ + GLint status; + gl_CompileShader (shader); + gl_GetShaderiv (shader, GL_COMPILE_STATUS, &status); + if (status == GL_FALSE) { + GLint infoLogLength; + GLchar *infoLog; + gl_GetShaderiv (shader, GL_INFO_LOG_LENGTH, &infoLogLength); + infoLog = (GLchar*) malloc (infoLogLength); + gl_GetShaderInfoLog (shader, infoLogLength, NULL, infoLog); + fprintf (stderr, "compile log: %s\n", infoLog); + free (infoLog); + } +} + +GLuint compileShaderSource(GLenum type, GLsizei count, const GLchar **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; + GLchar *infoLog; + gl_GetProgramiv (program, GL_INFO_LOG_LENGTH, &infoLogLength); + infoLog = (GLchar*) 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; +} + +void initShader(void) +{ + const GLsizei vertexShaderLines = sizeof(vertexShaderSource) / sizeof(GLchar*); + GLuint vertexShader = + compileShaderSource (GL_VERTEX_SHADER, vertexShaderLines, vertexShaderSource); + + const GLsizei fragmentShaderLines = sizeof(fragmentShaderSource) / sizeof(GLchar*); + GLuint fragmentShader = + compileShaderSource (GL_FRAGMENT_SHADER, fragmentShaderLines, fragmentShaderSource); + + GLuint program = createProgram (vertexShader, fragmentShader); + gl_UseProgram (program); + checkError ("initShader"); +} + +void initRendering(void) { - reportErrors ("at start of init"); glClearColor (0.0, 0.0, 0.0, 0.0); glShadeModel (GL_SMOOTH); - reportErrors ("at end of init"); + checkError ("initRendering"); +} + +void init(void) +{ + 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); } void triangle(void) { - reportErrors ("at start of triangle"); - glBegin (GL_TRIANGLES); - glColor3f (1.0, 0.0, 0.0); - glVertex2f (5.0, 5.0); - glColor3f (0.0, 1.0, 0.0); - glVertex2f (25.0, 5.0); - glColor3f (0.0, 0.0, 1.0); - glVertex2f (5.0, 25.0); - glEnd(); - reportErrors ("at end of triangle"); + gl_BindBuffer (GL_ARRAY_BUFFER, vertexBufferName); + glColorPointer (numColorComponents, GL_FLOAT, stride, bufferObjectPtr (0)); + glVertexPointer(numVertexComponents, GL_FLOAT, stride, + bufferObjectPtr (sizeof(GLfloat) * numColorComponents)); + glDrawArrays(GL_TRIANGLES, 0, numElements); + 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, @@ -117,7 +340,6 @@ void loadOrtho2Df(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) { @@ -127,7 +349,7 @@ void reshape (int w, int h) } glLoadMatrixf (m); glMatrixMode (GL_MODELVIEW); - reportErrors ("at end of reshape"); + checkError ("reshape"); } void keyboard(unsigned char key, int x, int y) @@ -143,11 +365,15 @@ int main(int argc, char** argv) { 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-3.0 context */ + if ((argc != 2) || (strcmp (argv[1], "classic") != 0)) { + glutInitContextVersion (3, 0); + glutInitContextFlags (GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG); + } glutInitWindowSize (500, 500); glutInitWindowPosition (100, 100); glutCreateWindow (argv[0]); + dumpInfo (); init (); glutDisplayFunc(display); glutReshapeFunc(reshape);