/** * Convolution with GLSL. * Note: uses GL_ARB_shader_objects, GL_ARB_vertex_shader, GL_ARB_fragment_shader, * not the OpenGL 2.0 shader API. * Author: Zack Rusin */ #include <GL/glew.h> #define GL_GLEXT_PROTOTYPES #include "readtex.h" #include <GL/glut.h> #include <stdio.h> #include <stdlib.h> #include <assert.h> #include <math.h> enum Filter { GAUSSIAN_BLUR, SHARPEN, MEAN_REMOVAL, EMBOSS, EDGE_DETECT, NO_FILTER, LAST }; #define QUIT LAST struct BoundingBox { float minx, miny, minz; float maxx, maxy, maxz; }; struct Texture { GLuint id; GLfloat x; GLfloat y; GLint width; GLint height; GLenum format; }; static const char *textureLocation = "../images/girl2.rgb"; static GLfloat viewRotx = 0.0, viewRoty = 0.0, viewRotz = 0.0; static struct BoundingBox box; static struct Texture texture; static GLuint program; static GLint menuId; static enum Filter filter = GAUSSIAN_BLUR; static void checkError(int line) { GLenum err = glGetError(); if (err) { printf("GL Error %s (0x%x) at line %d\n", gluErrorString(err), (int) err, line); } } static void loadAndCompileShader(GLuint shader, const char *text) { GLint stat; glShaderSource(shader, 1, (const GLchar **) &text, NULL); glCompileShader(shader); glGetShaderiv(shader, GL_COMPILE_STATUS, &stat); if (!stat) { GLchar log[1000]; GLsizei len; glGetShaderInfoLog(shader, 1000, &len, log); fprintf(stderr, "Problem compiling shader: %s\n", log); exit(1); } else { printf("Shader compiled OK\n"); } } static void readShader(GLuint shader, const char *filename) { const int max = 100*1000; int n; char *buffer = (char*) malloc(max); FILE *f = fopen(filename, "r"); if (!f) { fprintf(stderr, "Unable to open shader file %s\n", filename); exit(1); } n = fread(buffer, 1, max, f); printf("Read %d bytes from shader file %s\n", n, filename); if (n > 0) { buffer[n] = 0; loadAndCompileShader(shader, buffer); } fclose(f); free(buffer); } static void checkLink(GLuint prog) { GLint stat; glGetProgramiv(prog, GL_LINK_STATUS, &stat); if (!stat) { GLchar log[1000]; GLsizei len; glGetProgramInfoLog(prog, 1000, &len, log); fprintf(stderr, "Linker error:\n%s\n", log); } else { fprintf(stderr, "Link success!\n"); } } static void fillConvolution(GLint *k, GLfloat *scale, GLfloat *color) { switch(filter) { case GAUSSIAN_BLUR: k[0] = 1; k[1] = 2; k[2] = 1; k[3] = 2; k[4] = 4; k[5] = 2; k[6] = 1; k[7] = 2; k[8] = 1; *scale = 1./16.; break; case SHARPEN: k[0] = 0; k[1] = -2; k[2] = 0; k[3] = -2; k[4] = 11; k[5] = -2; k[6] = 0; k[7] = -2; k[8] = 0; *scale = 1./3.; break; case MEAN_REMOVAL: k[0] = -1; k[1] = -1; k[2] = -1; k[3] = -1; k[4] = 9; k[5] = -1; k[6] = -1; k[7] = -1; k[8] = -1; *scale = 1./1.; break; case EMBOSS: k[0] = -1; k[1] = 0; k[2] = -1; k[3] = 0; k[4] = 4; k[5] = 0; k[6] = -1; k[7] = 0; k[8] = -1; *scale = 1./1.; color[0] = 0.5; color[1] = 0.5; color[2] = 0.5; color[3] = 0.5; break; case EDGE_DETECT: k[0] = 1; k[1] = 1; k[2] = 1; k[3] = 0; k[4] = 0; k[5] = 0; k[6] = -1; k[7] = -1; k[8] = -1; *scale = 1.; color[0] = 0.5; color[1] = 0.5; color[2] = 0.5; color[3] = 0.5; break; case NO_FILTER: k[0] = 0; k[1] = 0; k[2] = 0; k[3] = 0; k[4] = 1; k[5] = 0; k[6] = 0; k[7] = 0; k[8] = 0; *scale = 1.; break; default: assert(!"Unhandled switch value"); } } static void setupConvolution() { GLint *kernel = (GLint*)malloc(sizeof(GLint) * 9); GLfloat scale; GLfloat *vecKer = (GLfloat*)malloc(sizeof(GLfloat) * 9 * 4); GLuint loc; GLuint i; GLfloat baseColor[4]; baseColor[0] = 0; baseColor[1] = 0; baseColor[2] = 0; baseColor[3] = 0; fillConvolution(kernel, &scale, baseColor); /*vector of 4*/ for (i = 0; i < 9; ++i) { vecKer[i*4 + 0] = kernel[i]; vecKer[i*4 + 1] = kernel[i]; vecKer[i*4 + 2] = kernel[i]; vecKer[i*4 + 3] = kernel[i]; } loc = glGetUniformLocationARB(program, "KernelValue"); glUniform4fv(loc, 9, vecKer); loc = glGetUniformLocationARB(program, "ScaleFactor"); glUniform4f(loc, scale, scale, scale, scale); loc = glGetUniformLocationARB(program, "BaseColor"); glUniform4f(loc, baseColor[0], baseColor[1], baseColor[2], baseColor[3]); free(vecKer); free(kernel); } static void createProgram(const char *vertProgFile, const char *fragProgFile) { GLuint fragShader = 0, vertShader = 0; program = glCreateProgram(); if (vertProgFile) { vertShader = glCreateShader(GL_VERTEX_SHADER); readShader(vertShader, vertProgFile); glAttachShader(program, vertShader); } if (fragProgFile) { fragShader = glCreateShader(GL_FRAGMENT_SHADER); readShader(fragShader, fragProgFile); glAttachShader(program, fragShader); } glLinkProgram(program); checkLink(program); glUseProgram(program); /* assert(glIsProgram(program)); assert(glIsShader(fragShader)); assert(glIsShader(vertShader)); */ checkError(__LINE__); {/*texture*/ GLuint texLoc = glGetUniformLocationARB(program, "srcTex"); glUniform1iARB(texLoc, 0); } {/*setup offsets */ float offsets[] = { 1.0 / texture.width, 1.0 / texture.height, 0.0 , 1.0 / texture.height, -1.0 / texture.width, 1.0 / texture.height, 1.0 / texture.width, 0.0, 0.0 , 0.0, -1.0 / texture.width, 0.0, 1.0 / texture.width, -1.0 / texture.height, 0.0 , -1.0 / texture.height, -1.0 / texture.width, -1.0 / texture.height }; GLuint offsetLoc = glGetUniformLocationARB(program, "Offset"); glUniform2fv(offsetLoc, 9, offsets); } setupConvolution(); checkError(__LINE__); } static void readTexture(const char *filename) { GLubyte *data; texture.x = 0; texture.y = 0; glGenTextures(1, &texture.id); glBindTexture(GL_TEXTURE_2D, texture.id); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); data = LoadRGBImage(filename, &texture.width, &texture.height, &texture.format); if (!data) { printf("Error: couldn't load texture image '%s'\n", filename); exit(1); } printf("Texture %s (%d x %d)\n", filename, texture.width, texture.height); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture.width, texture.height, 0, texture.format, GL_UNSIGNED_BYTE, data); } static void menuSelected(int entry) { switch (entry) { case QUIT: exit(0); break; default: filter = (enum Filter)entry; } setupConvolution(); glutPostRedisplay(); } static void menuInit() { menuId = glutCreateMenu(menuSelected); glutAddMenuEntry("Gaussian blur", GAUSSIAN_BLUR); glutAddMenuEntry("Sharpen", SHARPEN); glutAddMenuEntry("Mean removal", MEAN_REMOVAL); glutAddMenuEntry("Emboss", EMBOSS); glutAddMenuEntry("Edge detect", EDGE_DETECT); glutAddMenuEntry("None", NO_FILTER); glutAddMenuEntry("Quit", QUIT); glutAttachMenu(GLUT_RIGHT_BUTTON); } static void init() { if (!glutExtensionSupported("GL_ARB_shader_objects") || !glutExtensionSupported("GL_ARB_vertex_shader") || !glutExtensionSupported("GL_ARB_fragment_shader")) { fprintf(stderr, "Sorry, this program requires GL_ARB_shader_objects, GL_ARB_vertex_shader, and GL_ARB_fragment_shader\n"); exit(1); } fprintf(stderr, "GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); fprintf(stderr, "GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); fprintf(stderr, "GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR)); menuInit(); readTexture(textureLocation); createProgram("convolution.vert", "convolution.frag"); glEnable(GL_TEXTURE_2D); glClearColor(1.0, 1.0, 1.0, 1.0); /*glShadeModel(GL_SMOOTH);*/ glShadeModel(GL_FLAT); } static void reshape(int width, int height) { glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); box.minx = 0; box.maxx = width; box.miny = 0; box.maxy = height; box.minz = 0; box.maxz = 1; glOrtho(box.minx, box.maxx, box.miny, box.maxy, -999999, 999999); glMatrixMode(GL_MODELVIEW); } static void keyPress(unsigned char key, int x, int y) { switch(key) { case 27: exit(0); default: return; } glutPostRedisplay(); } static void special(int k, int x, int y) { switch (k) { case GLUT_KEY_UP: viewRotx += 2.0; break; case GLUT_KEY_DOWN: viewRotx -= 2.0; break; case GLUT_KEY_LEFT: viewRoty += 2.0; break; case GLUT_KEY_RIGHT: viewRoty -= 2.0; break; default: return; } glutPostRedisplay(); } static void draw() { GLfloat center[2]; GLfloat anchor[2]; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glPushMatrix(); center[0] = box.maxx/2; center[1] = box.maxy/2; anchor[0] = center[0] - texture.width/2; anchor[1] = center[1] - texture.height/2; glTranslatef(center[0], center[1], 0); glRotatef(viewRotx, 1.0, 0.0, 0.0); glRotatef(viewRoty, 0.0, 1.0, 0.0); glRotatef(viewRotz, 0.0, 0.0, 1.0); glTranslatef(-center[0], -center[1], 0); glTranslatef(anchor[0], anchor[1], 0); glBegin(GL_TRIANGLE_STRIP); { glColor3f(1., 0., 0.); glTexCoord2f(0, 0); glVertex3f(0, 0, 0); glColor3f(0., 1., 0.); glTexCoord2f(0, 1.0); glVertex3f(0, texture.height, 0); glColor3f(1., 0., 0.); glTexCoord2f(1.0, 0); glVertex3f(texture.width, 0, 0); glColor3f(0., 1., 0.); glTexCoord2f(1, 1); glVertex3f(texture.width, texture.height, 0); } glEnd(); glPopMatrix(); glutSwapBuffers(); } int main(int argc, char **argv) { glutInit(&argc, argv); glutInitWindowSize(400, 400); glutInitDisplayMode(GLUT_RGB | GLUT_ALPHA | GLUT_DOUBLE); if (!glutCreateWindow("Image Convolutions")) { fprintf(stderr, "Couldn't create window!\n"); exit(1); } glewInit(); init(); glutReshapeFunc(reshape); glutKeyboardFunc(keyPress); glutSpecialFunc(special); glutDisplayFunc(draw); glutMainLoop(); return 0; }