/** * Test OpenGL 2.0 dx/dy functions for texcoords. * Brian Paul * 2 May 2007 * * NOTE: resize the window to observe how the partial derivatives of * the texcoords change. */ #include <assert.h> #include <string.h> #include <stdio.h> #include <stdlib.h> #include <math.h> #include <GL/gl.h> #include <GL/glut.h> #include <GL/glext.h> #include "extfuncs.h" #include "shaderutil.h" static char *FragProgFile = NULL; static char *VertProgFile = NULL; static GLuint fragShader; static GLuint vertShader; static GLuint program; static GLuint SphereList, RectList, CurList; static GLint win = 0; static GLboolean anim = GL_TRUE; static GLfloat xRot = 0.0f, yRot = 0.0f; static void Redisplay(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glRotatef(xRot, 1.0f, 0.0f, 0.0f); glRotatef(yRot, 0.0f, 1.0f, 0.0f); glCallList(CurList); glPopMatrix(); glutSwapBuffers(); } static void Idle(void) { yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1; glutPostRedisplay(); } static void Reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.0f, 0.0f, -15.0f); } static void CleanUp(void) { glDeleteShader_func(fragShader); glDeleteShader_func(vertShader); glDeleteProgram_func(program); glutDestroyWindow(win); } static void Key(unsigned char key, int x, int y) { (void) x; (void) y; switch(key) { case ' ': case 'a': anim = !anim; if (anim) glutIdleFunc(Idle); else glutIdleFunc(NULL); break; case 'o': if (CurList == SphereList) CurList = RectList; else CurList = SphereList; break; case 27: CleanUp(); exit(0); break; } glutPostRedisplay(); } static void SpecialKey(int key, int x, int y) { const GLfloat step = 3.0f; (void) x; (void) y; switch(key) { case GLUT_KEY_UP: xRot -= step; break; case GLUT_KEY_DOWN: xRot += step; break; case GLUT_KEY_LEFT: yRot -= step; break; case GLUT_KEY_RIGHT: yRot += step; break; } glutPostRedisplay(); } static void MakeSphere(void) { GLUquadricObj *obj = gluNewQuadric(); SphereList = glGenLists(1); gluQuadricTexture(obj, GL_TRUE); glNewList(SphereList, GL_COMPILE); gluSphere(obj, 2.0f, 30, 15); glEndList(); } static void MakeRect(void) { RectList = glGenLists(1); glNewList(RectList, GL_COMPILE); glBegin(GL_POLYGON); glTexCoord2f(0, 0); glVertex2f(-2, -2); glTexCoord2f(1, 0); glVertex2f( 2, -2); glTexCoord2f(1, 1); glVertex2f( 2, 2); glTexCoord2f(0, 1); glVertex2f(-2, 2); glEnd(); glEndList(); } static void Init(void) { static const char *fragShaderText = "void main() {\n" " gl_FragColor = abs(dFdy(gl_TexCoord[0])) * 50.0;\n" " // gl_FragColor = gl_TexCoord[0];\n" "}\n"; static const char *vertShaderText = "void main() {\n" " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" " gl_TexCoord[0] = gl_MultiTexCoord0;\n" "}\n"; if (!ShadersSupported()) exit(1); GetExtensionFuncs(); vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText); fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText); program = LinkShaders(vertShader, fragShader); glUseProgram_func(program); /*assert(glGetError() == 0);*/ glClearColor(0.3f, 0.3f, 0.3f, 0.0f); glEnable(GL_DEPTH_TEST); MakeSphere(); MakeRect(); CurList = SphereList; printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER)); assert(glIsProgram_func(program)); assert(glIsShader_func(fragShader)); assert(glIsShader_func(vertShader)); glColor3f(1, 0, 0); } static void ParseOptions(int argc, char *argv[]) { int i; for (i = 1; i < argc; i++) { if (strcmp(argv[i], "-fs") == 0) { FragProgFile = argv[i+1]; } else if (strcmp(argv[i], "-vs") == 0) { VertProgFile = argv[i+1]; } } } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowPosition( 0, 0); glutInitWindowSize(200, 200); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); win = glutCreateWindow(argv[0]); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutSpecialFunc(SpecialKey); glutDisplayFunc(Redisplay); if (anim) glutIdleFunc(Idle); ParseOptions(argc, argv); Init(); glutMainLoop(); return 0; }