/** * Exercise all available GLSL texture samplers. * * Copyright (C) 2009 VMware, Inc. All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /** * We generate a fragment shader which uses the maximum number of supported * texture samplers. * For each sampler we create a separate texture. Each texture has a * single strip of color at a different intensity. The fragment shader * samples all the textures at the same coordinate and sums the values. * The result should be a quad with rows of colors of increasing intensity * from bottom to top. * * Brian Paul * 1 Jan 2009 */ #include <assert.h> #include <math.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <GL/glew.h> #include "GL/glut.h" #include "readtex.h" #include "shaderutil.h" #define MAX_SAMPLERS 128 static const char *Demo = "samplers"; static GLuint Program; static GLint NumSamplers; static GLuint Textures[MAX_SAMPLERS]; static GLfloat Xrot = 0.0, Yrot = .0, Zrot = 0.0; static GLfloat EyeDist = 10; static GLboolean Anim = GL_FALSE; static void DrawPolygon(GLfloat size) { glPushMatrix(); glNormal3f(0, 0, 1); glBegin(GL_POLYGON); glMultiTexCoord2f(GL_TEXTURE0, 0, 0); glVertex2f(-size, -size); glMultiTexCoord2f(GL_TEXTURE0, 1, 0); glVertex2f( size, -size); glMultiTexCoord2f(GL_TEXTURE0, 1, 1); glVertex2f( size, size); glMultiTexCoord2f(GL_TEXTURE0, 0, 1); glVertex2f(-size, size); glEnd(); glPopMatrix(); } static void draw(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glTranslatef(0.0, 0.0, -EyeDist); glRotatef(Zrot, 0, 0, 1); glRotatef(Yrot, 0, 1, 0); glRotatef(Xrot, 1, 0, 0); DrawPolygon(3.0); glPopMatrix(); glutSwapBuffers(); } static void idle(void) { GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME); Yrot = t; glutPostRedisplay(); } static void key(unsigned char k, int x, int y) { (void) x; (void) y; switch (k) { case ' ': case 'a': Anim = !Anim; if (Anim) glutIdleFunc(idle); else glutIdleFunc(NULL); break; case 'z': EyeDist -= 0.5; if (EyeDist < 3.0) EyeDist = 3.0; break; case 'Z': EyeDist += 0.5; if (EyeDist > 90.0) EyeDist = 90; break; case 27: exit(0); } glutPostRedisplay(); } static void specialkey(int key, int x, int y) { GLfloat step = 2.0; (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(); } /* new window size or exposure */ static void Reshape(int width, int height) { GLfloat ar = (float) width / (float) height; glViewport(0, 0, (GLint)width, (GLint)height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(-2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } static void InitTextures(void) { const GLint size = MAX_SAMPLERS; GLubyte *texImage; GLenum filter = GL_NEAREST; GLint stripeSize; GLint s; texImage = (GLubyte *) malloc(size * size * 4); glGenTextures(NumSamplers, Textures); /* size of texels stripe */ stripeSize = size / NumSamplers; /* create a texture for each sampler */ for (s = 0; s < NumSamplers; s++) { GLint x, y, ypos; GLubyte intensity = 31 + s * (256-32) / (NumSamplers - 1); printf("Texture %d: color = %d, %d, %d\n", s, (int) intensity, 0, (int) intensity ); /* initialize the texture to black */ memset(texImage, 0, size * size * 4); /* set a stripe of texels to the intensity value */ ypos = s * stripeSize; for (y = 0; y < stripeSize; y++) { for (x = 0; x < size; x++) { GLint k = 4 * ((ypos + y) * size + x); if (x < size / 2) { texImage[k + 0] = intensity; texImage[k + 1] = intensity; texImage[k + 2] = 0; texImage[k + 3] = 255; } else { texImage[k + 0] = 255 - intensity; texImage[k + 1] = 0; texImage[k + 2] = 0; texImage[k + 3] = 255; } } } glActiveTexture(GL_TEXTURE0 + s); glBindTexture(GL_TEXTURE_2D, Textures[s]); gluBuild2DMipmaps(GL_TEXTURE_2D, 4, size, size, GL_RGBA, GL_UNSIGNED_BYTE, texImage); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter); } free(texImage); } /** * Generate a fragment shader that uses the given number of samplers. */ static char * GenFragmentShader(GLint numSamplers) { const int maxLen = 10 * 1000; char *prog = (char *) malloc(maxLen); char *p = prog; int s; p += sprintf(p, "// Generated fragment shader:\n"); #ifndef SAMPLERS_ARRAY for (s = 0; s < numSamplers; s++) { p += sprintf(p, "uniform sampler2D tex%d;\n", s); } #else p += sprintf(p, "uniform sampler2D tex[%d];\n", numSamplers); #endif p += sprintf(p, "void main()\n"); p += sprintf(p, "{\n"); p += sprintf(p, " vec4 color = vec4(0.0);\n"); for (s = 0; s < numSamplers; s++) { #ifndef SAMPLERS_ARRAY p += sprintf(p, " color += texture2D(tex%d, gl_TexCoord[0].xy);\n", s); #else p += sprintf(p, " color += texture2D(tex[%d], gl_TexCoord[0].xy);\n", s); #endif } p += sprintf(p, " gl_FragColor = color;\n"); p += sprintf(p, "}\n"); assert(p - prog < maxLen); return prog; } /** Create & bind shader program */ static GLuint CreateProgram(void) { GLuint fragShader, vertShader, program; const char *vertShaderText = "void main() \n" "{ \n" " gl_TexCoord[0] = gl_MultiTexCoord0; \n" " gl_Position = ftransform(); \n" "} \n"; char *fragShaderText = GenFragmentShader(NumSamplers); printf("%s", fragShaderText); vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText); fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText); assert(vertShader); program = LinkShaders(vertShader, fragShader); glUseProgram(program); free(fragShaderText); return program; } static void InitProgram(void) { GLint s; Program = CreateProgram(); /* init sampler uniforms */ for (s = 0; s < NumSamplers; s++) { char uname[10]; GLint loc; #ifndef SAMPLERS_ARRAY sprintf(uname, "tex%d", s); #else sprintf(uname, "tex[%d]", s); #endif loc = glGetUniformLocation(Program, uname); assert(loc >= 0); glUniform1i(loc, s); } } static void InitGL(void) { if (!ShadersSupported()) { printf("GLSL not supported!\n"); exit(1); } printf("GL_RENDERER = %s\n", (const char *) glGetString(GL_RENDERER)); glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &NumSamplers); if (NumSamplers > MAX_SAMPLERS) NumSamplers = MAX_SAMPLERS; printf("Testing %d samplers\n", NumSamplers); InitTextures(); InitProgram(); glClearColor(.6, .6, .9, 0); glColor3f(1.0, 1.0, 1.0); printf("Each color corresponds to a separate sampler/texture.\n"); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowSize(500, 400); glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); glutCreateWindow(Demo); glewInit(); glutReshapeFunc(Reshape); glutKeyboardFunc(key); glutSpecialFunc(specialkey); glutDisplayFunc(draw); if (Anim) glutIdleFunc(idle); InitGL(); glutMainLoop(); return 0; }