vertex_and_fragment_program.rar_Cg

/* 02_vertex_and_fragment_program.c - OpenGL-based example using a Cg vertex and a Cg fragment programs from Chapter 2 of "The Cg Tutorial" (Addison-Wesley, ISBN 0321194969). */ /* Requires the OpenGL Utility Toolkit (GLUT) and Cg runtime (version 1.0 or higher). */ #include <stdio.h> /* for printf and NULL */ #include <stdlib.h> /* for exit */ #include <math.h> /* for sin and cos */ #if __APPLE__ #include <GLUT/glut.h> #else #include <GL/glut.h> #endif #include <Cg/cg.h> /* Can't include this? Is Cg Toolkit installed! */ #include <Cg/cgGL.h> static CGcontext myCgContext; static CGprofile myCgVertexProfile, myCgFragmentProfile; static CGprogram myCgVertexProgram, myCgFragmentProgram; static const char *myProgramName = "02_vertex_and_fragment_program", *myVertexProgramFileName = "C2E1v_green.cg", /* Page 38 */ *myVertexProgramName = "C2E1v_green", *myFragmentProgramFileName = "C2E2f_passthru.cg", /* Page 53 */ *myFragmentProgramName = "C2E2f_passthru"; static void checkForCgError(const char *situation) { CGerror error; const char *string = cgGetLastErrorString(&error); if (error != CG_NO_ERROR) { printf("%s: %s: %s\n", myProgramName, situation, string); if (error == CG_COMPILER_ERROR) { printf("%s\n", cgGetLastListing(myCgContext)); } exit(1); } } /* Forward declared GLUT callbacks registered by main. */ static void display(void); static void keyboard(unsigned char c, int x, int y); int main(int argc, char **argv) { glutInitWindowSize(400, 400); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); glutInit(&argc, argv); glutCreateWindow(myProgramName); glutDisplayFunc(display); glutKeyboardFunc(keyboard); glClearColor(0.1, 0.3, 0.6, 0.0); /* Blue background */ myCgContext = cgCreateContext(); checkForCgError("creating context"); myCgVertexProfile = cgGLGetLatestProfile(CG_GL_VERTEX); cgGLSetOptimalOptions(myCgVertexProfile); checkForCgError("selecting vertex profile"); myCgVertexProgram = cgCreateProgramFromFile( myCgContext, /* Cg runtime context */ CG_SOURCE, /* Program in human-readable form */ myVertexProgramFileName, /* Name of file containing program */ myCgVertexProfile, /* Profile: OpenGL ARB vertex program */ myVertexProgramName, /* Entry function name */ NULL); /* No extra compiler options */ checkForCgError("creating vertex program from file"); cgGLLoadProgram(myCgVertexProgram); checkForCgError("loading vertex program"); myCgFragmentProfile = cgGLGetLatestProfile(CG_GL_FRAGMENT); cgGLSetOptimalOptions(myCgFragmentProfile); checkForCgError("selecting fragment profile"); myCgFragmentProgram = cgCreateProgramFromFile( myCgContext, /* Cg runtime context */ CG_SOURCE, /* Program in human-readable form */ myFragmentProgramFileName, /* Name of file containing program */ myCgFragmentProfile, /* Profile: OpenGL ARB vertex program */ myFragmentProgramName, /* Entry function name */ NULL); /* No extra compiler options */ checkForCgError("creating fragment program from file"); cgGLLoadProgram(myCgFragmentProgram); checkForCgError("loading fragment program"); glutMainLoop(); return 0; } static void drawStar(float x, float y, int starPoints, float R, float r) { int i; double piOverStarPoints = 3.14159 / starPoints, angle = 0.0; glBegin(GL_TRIANGLE_FAN); glVertex2f(x, y); /* Center of star */ /* Emit exterior vertices for star's points. */ for (i=0; i<starPoints; i++) { glVertex2f(x + R*cos(angle), y + R*sin(angle)); angle += piOverStarPoints; glVertex2f(x + r*cos(angle), y + r*sin(angle)); angle += piOverStarPoints; } /* End by repeating first exterior vertex of star. */ angle = 0; glVertex2f(x + R*cos(angle), y + R*sin(angle)); glEnd(); } static void drawStars(void) { /* star outer inner */ /* x y Points radius radius */ /* ===== ===== ====== ====== ====== */ drawStar(-0.1, 0, 5, 0.5, 0.2); drawStar(-0.84, 0.1, 5, 0.3, 0.12); drawStar( 0.92, -0.5, 5, 0.25, 0.11); drawStar( 0.3, 0.97, 5, 0.3, 0.1); drawStar( 0.94, 0.3, 5, 0.5, 0.2); drawStar(-0.97, -0.8, 5, 0.6, 0.2); } static void display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); cgGLBindProgram(myCgVertexProgram); checkForCgError("binding vertex program"); cgGLEnableProfile(myCgVertexProfile); checkForCgError("enabling vertex profile"); cgGLBindProgram(myCgFragmentProgram); checkForCgError("binding fragment program"); cgGLEnableProfile(myCgFragmentProfile); checkForCgError("enabling fragment profile"); drawStars(); cgGLDisableProfile(myCgVertexProfile); checkForCgError("disabling vertex profile"); cgGLDisableProfile(myCgFragmentProfile); checkForCgError("disabling fragment profile"); glutSwapBuffers(); } static void keyboard(unsigned char c, int x, int y) { switch (c) { case 27: /* Esc key */ /* Demonstrate proper deallocation of Cg runtime data structures. Not strictly necessary if we are simply going to exit. */ cgDestroyProgram(myCgVertexProgram); cgDestroyProgram(myCgFragmentProgram); cgDestroyContext(myCgContext); exit(0); break; } }