| /** |
| * 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; |
| } |