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/glew.h>
  32 #include "GL/glut.h"
  33 #include "readtex.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 = 0.0, Yrot = .0, Zrot = 0.0;
  51 static GLfloat EyeDist = 10;
  52 static GLboolean Anim = GL_TRUE;
  53 static GLboolean UseArrays = GL_TRUE;
  54 static GLboolean UseVBO = GL_TRUE;
  55 static GLuint VBO = 0;
  56
  57 static GLint VertCoord_attr = -1, TexCoord0_attr = -1, TexCoord1_attr = -1;
  58
  59
  60 /* value[0] = tex unit */
  61 static struct uniform_info Uniforms[] = {
  62    { "tex1",  1, GL_SAMPLER_2D, { 0, 0, 0, 0 }, -1 },
  63    { "tex2",  1, GL_SAMPLER_2D, { 1, 0, 0, 0 }, -1 },
  64    END_OF_UNIFORMS
  65 };
  66
  67
  68 static const GLfloat Tex0Coords[4][2] = {
  69    { 0.0, 0.0 }, { 2.0, 0.0 }, { 2.0, 2.0 }, { 0.0, 2.0 }
  70 };
  71
  72 static const GLfloat Tex1Coords[4][2] = {
  73    { 0.0, 0.0 }, { 1.0, 0.0 }, { 1.0, 1.0 }, { 0.0, 1.0 }
  74 };
  75
  76 static const GLfloat VertCoords[4][2] = {
  77    { -3.0, -3.0 }, { 3.0, -3.0 }, { 3.0, 3.0 }, { -3.0, 3.0 }
  78 };
  79
  80
  81
  82 static void
  83 SetupVertexBuffer(void)
  84 {
  85    glGenBuffersARB(1, &VBO);
  86    glBindBufferARB(GL_ARRAY_BUFFER_ARB, VBO);
  87
  88    glBufferDataARB(GL_ARRAY_BUFFER_ARB,
  89                         sizeof(VertCoords) +
  90                         sizeof(Tex0Coords) +
  91                         sizeof(Tex1Coords),
  92                         NULL,
  93                         GL_STATIC_DRAW_ARB);
  94
  95    /* non-interleaved vertex arrays */
  96
  97    glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
  98                            0,                   /* offset */
  99                            sizeof(VertCoords),  /* size */
 100                            VertCoords);         /* data */
 101
 102    glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
 103                            sizeof(VertCoords),  /* offset */
 104                            sizeof(Tex0Coords),  /* size */
 105                            Tex0Coords);         /* data */
 106
 107    glBufferSubDataARB(GL_ARRAY_BUFFER_ARB,
 108                            sizeof(VertCoords) +
 109                            sizeof(Tex0Coords),  /* offset */
 110                            sizeof(Tex1Coords),  /* size */
 111                            Tex1Coords);         /* data */
 112
 113    glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
 114 }
 115
 116
 117 static void
 118 DrawPolygonArray(void)
 119 {
 120    void *vertPtr, *tex0Ptr, *tex1Ptr;
 121
 122    if (UseVBO) {
 123       glBindBufferARB(GL_ARRAY_BUFFER_ARB, VBO);
 124       vertPtr = (void *) 0;
 125       tex0Ptr = (void *) sizeof(VertCoords);
 126       tex1Ptr = (void *) (sizeof(VertCoords) + sizeof(Tex0Coords));
 127    }
 128    else {
 129       glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
 130       vertPtr = VertCoords;
 131       tex0Ptr = Tex0Coords;
 132       tex1Ptr = Tex1Coords;
 133    }
 134
 135    if (VertCoord_attr >= 0) {
 136       glVertexAttribPointer(VertCoord_attr, 2, GL_FLOAT, GL_FALSE,
 137                                  0, vertPtr);
 138       glEnableVertexAttribArray(VertCoord_attr);
 139    }
 140    else {
 141       glVertexPointer(2, GL_FLOAT, 0, vertPtr);
 142       glEnableClientState(GL_VERTEX_ARRAY);
 143    }
 144
 145    glVertexAttribPointer(TexCoord0_attr, 2, GL_FLOAT, GL_FALSE,
 146                               0, tex0Ptr);
 147    glEnableVertexAttribArray(TexCoord0_attr);
 148
 149    glVertexAttribPointer(TexCoord1_attr, 2, GL_FLOAT, GL_FALSE,
 150                               0, tex1Ptr);
 151    glEnableVertexAttribArray(TexCoord1_attr);
 152
 153    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 154
 155    glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
 156 }
 157
 158
 159 static void
 160 DrawPolygonVert(void)
 161 {
 162    GLuint i;
 163
 164    glBegin(GL_TRIANGLE_FAN);
 165
 166    for (i = 0; i < 4; i++) {
 167       glVertexAttrib2fv(TexCoord0_attr, Tex0Coords[i]);
 168       glVertexAttrib2fv(TexCoord1_attr, Tex1Coords[i]);
 169
 170       if (VertCoord_attr >= 0)
 171          glVertexAttrib2fv(VertCoord_attr, VertCoords[i]);
 172       else
 173          glVertex2fv(VertCoords[i]);
 174    }
 175
 176    glEnd();
 177 }
 178
 179
 180 static void
 181 draw(void)
 182 {
 183    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 184
 185    glPushMatrix(); /* modelview matrix */
 186       glTranslatef(0.0, 0.0, -EyeDist);
 187       glRotatef(Zrot, 0, 0, 1);
 188       glRotatef(Yrot, 0, 1, 0);
 189       glRotatef(Xrot, 1, 0, 0);
 190
 191       if (UseArrays)
 192          DrawPolygonArray();
 193       else
 194          DrawPolygonVert();
 195
 196    glPopMatrix();
 197
 198    glutSwapBuffers();
 199 }
 200
 201
 202 static void
 203 idle(void)
 204 {
 205    GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
 206    Yrot = t;
 207    glutPostRedisplay();
 208 }
 209
 210
 211 static void
 212 key(unsigned char k, int x, int y)
 213 {
 214    (void) x;
 215    (void) y;
 216    switch (k) {
 217    case 'a':
 218       UseArrays = !UseArrays;
 219       printf("Arrays: %d\n", UseArrays);
 220       break;
 221    case 'v':
 222       UseVBO = !UseVBO;
 223       printf("Use VBO: %d\n", UseVBO);
 224       break;
 225    case ' ':
 226       Anim = !Anim;
 227       if (Anim)
 228          glutIdleFunc(idle);
 229       else
 230          glutIdleFunc(NULL);
 231       break;
 232    case 'z':
 233       EyeDist -= 0.5;
 234       if (EyeDist < 3.0)
 235          EyeDist = 3.0;
 236       break;
 237    case 'Z':
 238       EyeDist += 0.5;
 239       if (EyeDist > 90.0)
 240          EyeDist = 90;
 241       break;
 242    case 27:
 243       exit(0);
 244    }
 245    glutPostRedisplay();
 246 }
 247
 248
 249 static void
 250 specialkey(int key, int x, int y)
 251 {
 252    GLfloat step = 2.0;
 253    (void) x;
 254    (void) y;
 255    switch (key) {
 256    case GLUT_KEY_UP:
 257       Xrot += step;
 258       break;
 259    case GLUT_KEY_DOWN:
 260       Xrot -= step;
 261       break;
 262    case GLUT_KEY_LEFT:
 263       Yrot -= step;
 264       break;
 265    case GLUT_KEY_RIGHT:
 266       Yrot += step;
 267       break;
 268    }
 269    glutPostRedisplay();
 270 }
 271
 272
 273 /* new window size or exposure */
 274 static void
 275 Reshape(int width, int height)
 276 {
 277    GLfloat ar = (float) width / (float) height;
 278    glViewport(0, 0, (GLint)width, (GLint)height);
 279    glMatrixMode(GL_PROJECTION);
 280    glLoadIdentity();
 281    glFrustum(-2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0);
 282    glMatrixMode(GL_MODELVIEW);
 283    glLoadIdentity();
 284 }
 285
 286
 287 static void
 288 InitTextures(void)
 289 {
 290    GLenum filter = GL_LINEAR;
 291    int i;
 292
 293    for (i = 0; i < 2; i++) {
 294       GLint imgWidth, imgHeight;
 295       GLenum imgFormat;
 296       GLubyte *image = NULL;
 297
 298       image = LoadRGBImage(TexFiles[i], &imgWidth, &imgHeight, &imgFormat);
 299       if (!image) {
 300          printf("Couldn't read %s\n", TexFiles[i]);
 301          exit(0);
 302       }
 303
 304       glActiveTexture(GL_TEXTURE0 + i);
 305       glBindTexture(GL_TEXTURE_2D, 42 + i);
 306       gluBuild2DMipmaps(GL_TEXTURE_2D, 4, imgWidth, imgHeight,
 307                         imgFormat, GL_UNSIGNED_BYTE, image);
 308       free(image);
 309
 310       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 311       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 312       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
 313       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
 314    }
 315 }
 316
 317
 318 static GLuint
 319 CreateProgram(const char *vertProgFile, const char *fragProgFile,
 320               struct uniform_info *uniforms)
 321 {
 322    GLuint fragShader, vertShader, program;
 323
 324    vertShader = CompileShaderFile(GL_VERTEX_SHADER, vertProgFile);
 325    fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, fragProgFile);
 326    assert(vertShader);
 327    program = LinkShaders(vertShader, fragShader);
 328
 329    glUseProgram(program);
 330
 331    SetUniformValues(program, uniforms);
 332    PrintUniforms(Uniforms);
 333
 334    assert(ValidateShaderProgram(program));
 335
 336    VertCoord_attr = glGetAttribLocation(program, "VertCoord");
 337    if (VertCoord_attr > 0) {
 338       /* We want the VertCoord attrib to have position zero so that
 339        * the call to glVertexAttrib(0, xyz) triggers vertex processing.
 340        * Otherwise, if TexCoord0 or TexCoord1 gets position 0 we'd have
 341        * to set that attribute last (which is a PITA to manage).
 342        */
 343       glBindAttribLocation(program, 0, "VertCoord");
 344       /* re-link */
 345       glLinkProgram(program);
 346       /* VertCoord_attr should be zero now */
 347       VertCoord_attr = glGetAttribLocation(program, "VertCoord");
 348       assert(VertCoord_attr == 0);
 349    }
 350
 351    TexCoord0_attr = glGetAttribLocation(program, "TexCoord0");
 352    TexCoord1_attr = glGetAttribLocation(program, "TexCoord1");
 353
 354    printf("TexCoord0_attr = %d\n", TexCoord0_attr);
 355    printf("TexCoord1_attr = %d\n", TexCoord1_attr);
 356    printf("VertCoord_attr = %d\n", VertCoord_attr);
 357
 358    return program;
 359 }
 360
 361
 362 static void
 363 InitPrograms(void)
 364 {
 365    Program = CreateProgram(VertFile, FragFile, Uniforms);
 366 }
 367
 368
 369 static void
 370 InitGL(void)
 371 {
 372    if (!ShadersSupported())
 373       exit(1);
 374
 375    printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
 376    printf("Usage:\n");
 377    printf("  a     - toggle arrays vs. immediate mode rendering\n");
 378    printf("  v     - toggle VBO usage for array rendering\n");
 379    printf("  z/Z   - change viewing distance\n");
 380    printf("  SPACE - toggle animation\n");
 381    printf("  Esc   - exit\n");
 382
 383    InitTextures();
 384    InitPrograms();
 385
 386    SetupVertexBuffer();
 387
 388    glEnable(GL_DEPTH_TEST);
 389
 390    glClearColor(.6, .6, .9, 0);
 391    glColor3f(1.0, 1.0, 1.0);
 392 }
 393
 394
 395 int
 396 main(int argc, char *argv[])
 397 {
 398    glutInit(&argc, argv);
 399    glutInitWindowSize(500, 400);
 400    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
 401    glutCreateWindow(Demo);
 402    glewInit();
 403    glutReshapeFunc(Reshape);
 404    glutKeyboardFunc(key);
 405    glutSpecialFunc(specialkey);
 406    glutDisplayFunc(draw);
 407    if (Anim)
 408       glutIdleFunc(idle);
 409    InitGL();
 410    glutMainLoop();
 411    return 0;
 412 }