/** * "Mandelbrot" shader demo. Uses the example shaders from * chapter 15 (or 18) of the OpenGL Shading Language "orange" book. * 15 Jan 2007 */ #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 = "CH18-mandel.frag"; static char *VertProgFile = "CH18-mandel.vert"; /* program/shader objects */ static GLuint fragShader; static GLuint vertShader; static GLuint program; static struct uniform_info Uniforms[] = { /* vert */ { "LightPosition", 3, GL_FLOAT, { 0.1, 0.1, 9.0, 0}, -1 }, { "SpecularContribution", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 }, { "DiffuseContribution", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 }, { "Shininess", 1, GL_FLOAT, { 20.0, 0, 0, 0 }, -1 }, /* frag */ { "MaxIterations", 1, GL_FLOAT, { 12, 0, 0, 0 }, -1 }, { "Zoom", 1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 }, { "Xcenter", 1, GL_FLOAT, { -1.5, 0, 0, 0 }, -1 }, { "Ycenter", 1, GL_FLOAT, { .005, 0, 0, 0 }, -1 }, { "InnerColor", 3, GL_FLOAT, { 1, 0, 0, 0 }, -1 }, { "OuterColor1", 3, GL_FLOAT, { 0, 1, 0, 0 }, -1 }, { "OuterColor2", 3, GL_FLOAT, { 0, 0, 1, 0 }, -1 }, END_OF_UNIFORMS }; static GLint win = 0; static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f; static GLint uZoom, uXcenter, uYcenter; static GLfloat zoom = 1.0, xCenter = -1.5, yCenter = 0.0; static void Redisplay(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); /* set interactive uniform parameters */ glUniform1fv_func(uZoom, 1, &zoom); glUniform1fv_func(uXcenter, 1, &xCenter); glUniform1fv_func(uYcenter, 1, &yCenter); glPushMatrix(); glRotatef(xRot, 1.0f, 0.0f, 0.0f); glRotatef(yRot, 0.0f, 1.0f, 0.0f); glRotatef(zRot, 0.0f, 0.0f, 1.0f); glBegin(GL_POLYGON); glTexCoord2f(0, 0); glVertex2f(-1, -1); glTexCoord2f(1, 0); glVertex2f( 1, -1); glTexCoord2f(1, 1); glVertex2f( 1, 1); glTexCoord2f(0, 1); glVertex2f(-1, 1); glEnd(); glPopMatrix(); glFinish(); glFlush(); glutSwapBuffers(); } 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, -6.0f); } 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 'z': zoom *= 0.9; break; case 'Z': zoom /= 0.9; break; case 27: CleanUp(); exit(0); break; } glutPostRedisplay(); } static void SpecialKey(int key, int x, int y) { const GLfloat step = 0.1 * zoom; (void) x; (void) y; switch(key) { case GLUT_KEY_UP: yCenter += step; break; case GLUT_KEY_DOWN: yCenter -= step; break; case GLUT_KEY_LEFT: xCenter -= step; break; case GLUT_KEY_RIGHT: xCenter += step; break; } glutPostRedisplay(); } static void Init(void) { if (!ShadersSupported()) exit(1); GetExtensionFuncs(); vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile); fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile); program = LinkShaders(vertShader, fragShader); glUseProgram_func(program); InitUniforms(program, Uniforms); uZoom = glGetUniformLocation_func(program, "Zoom"); uXcenter = glGetUniformLocation_func(program, "Xcenter"); uYcenter = glGetUniformLocation_func(program, "Ycenter"); assert(glGetError() == 0); glClearColor(0.4f, 0.4f, 0.8f, 0.0f); 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(400, 400); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH); win = glutCreateWindow(argv[0]); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutSpecialFunc(SpecialKey); glutDisplayFunc(Redisplay); ParseOptions(argc, argv); Init(); glutMainLoop(); return 0; }