progs/glsl/multitex.c

   1 /**
   2  * Test multi-texturing with GL shading language.
   3  *
   4  * Copyright (C) 2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  20  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  22  */
  23
  24
  25
  26 #include <assert.h>
  27 #include <math.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include "GL/glut.h"
  32 #include "readtex.h"
  33 #include "extfuncs.h"
  34 #include "shaderutil.h"
  35
  36 static const char *Demo = "multitex";
  37
  38 static const char *VertFile = "multitex.vert";
  39 static const char *FragFile = "multitex.frag";
  40
  41 static const char *TexFiles[2] =
  42    {
  43       "../images/tile.rgb",
  44       "../images/tree2.rgba"
  45    };
  46
  47
  48 static GLuint Program;
  49
  50 static GLfloat Xrot = -90.0, Yrot = .0, Zrot = 0.0;
  51 static GLfloat EyeDist = 10;
  52 static GLboolean Anim = GL_TRUE;
  53
  54
  55 /* value[0] = tex unit */
  56 static struct uniform_info Uniforms[] = {
  57    { "tex1",  1, GL_INT, { 0, 0, 0, 0 }, -1 },
  58    { "tex2",  1, GL_INT, { 1, 0, 0, 0 }, -1 },
  59    END_OF_UNIFORMS
  60 };
  61
  62
  63 static void
  64 DrawPolygon(GLfloat size)
  65 {
  66    glPushMatrix();
  67    glRotatef(90, 1, 0, 0);
  68    glNormal3f(0, 0, 1);
  69    glBegin(GL_POLYGON);
  70
  71    glMultiTexCoord2f(GL_TEXTURE0, 0, 0);
  72    glMultiTexCoord2f(GL_TEXTURE1, 0, 0);
  73    glVertex2f(-size, -size);
  74
  75    glMultiTexCoord2f(GL_TEXTURE0, 2, 0);
  76    glMultiTexCoord2f(GL_TEXTURE1, 1, 0);
  77    glVertex2f( size, -size);
  78
  79    glMultiTexCoord2f(GL_TEXTURE0, 2, 2);
  80    glMultiTexCoord2f(GL_TEXTURE1, 1, 1);
  81    glVertex2f( size,  size);
  82
  83    glMultiTexCoord2f(GL_TEXTURE0, 0, 2);
  84    glMultiTexCoord2f(GL_TEXTURE1, 0, 1);
  85    glVertex2f(-size,  size);
  86
  87    glEnd();
  88    glPopMatrix();
  89 }
  90
  91
  92 static void
  93 draw(void)
  94 {
  95    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  96
  97    glPushMatrix(); /* modelview matrix */
  98       glTranslatef(0.0, 0.0, -EyeDist);
  99       glRotatef(Zrot, 0, 0, 1);
 100       glRotatef(Yrot, 0, 1, 0);
 101       glRotatef(Xrot, 1, 0, 0);
 102
 103       DrawPolygon(3.0);
 104
 105    glPopMatrix();
 106
 107    glutSwapBuffers();
 108 }
 109
 110
 111 static void
 112 idle(void)
 113 {
 114    GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
 115    Yrot = t;
 116    glutPostRedisplay();
 117 }
 118
 119
 120 static void
 121 key(unsigned char k, int x, int y)
 122 {
 123    (void) x;
 124    (void) y;
 125    switch (k) {
 126    case ' ':
 127    case 'a':
 128       Anim = !Anim;
 129       if (Anim)
 130          glutIdleFunc(idle);
 131       else
 132          glutIdleFunc(NULL);
 133       break;
 134    case 'z':
 135       EyeDist -= 0.5;
 136       if (EyeDist < 3.0)
 137          EyeDist = 3.0;
 138       break;
 139    case 'Z':
 140       EyeDist += 0.5;
 141       if (EyeDist > 90.0)
 142          EyeDist = 90;
 143       break;
 144    case 27:
 145       exit(0);
 146    }
 147    glutPostRedisplay();
 148 }
 149
 150
 151 static void
 152 specialkey(int key, int x, int y)
 153 {
 154    GLfloat step = 2.0;
 155    (void) x;
 156    (void) y;
 157    switch (key) {
 158    case GLUT_KEY_UP:
 159       Xrot += step;
 160       break;
 161    case GLUT_KEY_DOWN:
 162       Xrot -= step;
 163       break;
 164    case GLUT_KEY_LEFT:
 165       Yrot -= step;
 166       break;
 167    case GLUT_KEY_RIGHT:
 168       Yrot += step;
 169       break;
 170    }
 171    glutPostRedisplay();
 172 }
 173
 174
 175 /* new window size or exposure */
 176 static void
 177 Reshape(int width, int height)
 178 {
 179    GLfloat ar = (float) width / (float) height;
 180    glViewport(0, 0, (GLint)width, (GLint)height);
 181    glMatrixMode(GL_PROJECTION);
 182    glLoadIdentity();
 183    glFrustum(-2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0);
 184    glMatrixMode(GL_MODELVIEW);
 185    glLoadIdentity();
 186 }
 187
 188
 189 static void
 190 InitTextures(void)
 191 {
 192    GLenum filter = GL_LINEAR;
 193    int i;
 194
 195    for (i = 0; i < 2; i++) {
 196       GLint imgWidth, imgHeight;
 197       GLenum imgFormat;
 198       GLubyte *image = NULL;
 199
 200       image = LoadRGBImage(TexFiles[i], &imgWidth, &imgHeight, &imgFormat);
 201       if (!image) {
 202          printf("Couldn't read %s\n", TexFiles[i]);
 203          exit(0);
 204       }
 205
 206       glActiveTexture(GL_TEXTURE0 + i);
 207       glBindTexture(GL_TEXTURE_2D, 42 + i);
 208       gluBuild2DMipmaps(GL_TEXTURE_2D, 4, imgWidth, imgHeight,
 209                         imgFormat, GL_UNSIGNED_BYTE, image);
 210       free(image);
 211
 212       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 213       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 214       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
 215       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
 216    }
 217 }
 218
 219
 220 static GLuint
 221 CreateProgram(const char *vertProgFile, const char *fragProgFile,
 222               struct uniform_info *uniforms)
 223 {
 224    GLuint fragShader, vertShader, program;
 225
 226    vertShader = CompileShaderFile(GL_VERTEX_SHADER, vertProgFile);
 227    fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, fragProgFile);
 228    assert(vertShader);
 229    program = LinkShaders(vertShader, fragShader);
 230
 231    glUseProgram_func(program);
 232
 233    InitUniforms(program, uniforms);
 234
 235    return program;
 236 }
 237
 238
 239 static void
 240 InitPrograms(void)
 241 {
 242    Program = CreateProgram(VertFile, FragFile, Uniforms);
 243 }
 244
 245
 246 static void
 247 InitGL(void)
 248 {
 249    const char *version = (const char *) glGetString(GL_VERSION);
 250
 251    if (version[0] != '2' || version[1] != '.') {
 252       printf("Warning: this program expects OpenGL 2.0\n");
 253       /*exit(1);*/
 254    }
 255    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 256
 257    GetExtensionFuncs();
 258
 259    InitTextures();
 260    InitPrograms();
 261
 262    glEnable(GL_DEPTH_TEST);
 263
 264    glClearColor(.6, .6, .9, 0);
 265    glColor3f(1.0, 1.0, 1.0);
 266 }
 267
 268
 269 int
 270 main(int argc, char *argv[])
 271 {
 272    glutInit(&argc, argv);
 273    glutInitWindowSize(500, 400);
 274    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
 275    glutCreateWindow(Demo);
 276    glutReshapeFunc(Reshape);
 277    glutKeyboardFunc(key);
 278    glutSpecialFunc(specialkey);
 279    glutDisplayFunc(draw);
 280    if (Anim)
 281       glutIdleFunc(idle);
 282    InitGL();
 283    glutMainLoop();
 284    return 0;
 285 }