progs/tests/mipmap_view.c

   1 /*
   2  * Test mipmap generation and lod bias.
   3  *
   4  * Brian Paul
   5  * 17 March 2008
   6  */
   7
   8
   9 #include <assert.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <math.h>
  13 #include <GL/glut.h>
  14 #include <GL/glext.h>
  15
  16 #include "readtex.h"
  17
  18 #define TEXTURE_FILE "../images/arch.rgb"
  19
  20 static int TexWidth = 256, TexHeight = 256;
  21 static int WinWidth = 1044, WinHeight = 900;
  22 static GLfloat Bias = 0.0;
  23 static GLboolean ScaleQuads = GL_FALSE;
  24
  25
  26 static void
  27 PrintString(const char *s)
  28 {
  29    while (*s) {
  30       glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
  31       s++;
  32    }
  33 }
  34
  35
  36 static void
  37 Display(void)
  38 {
  39    int x, y, bias;
  40    char str[100];
  41    int texWidth = TexWidth, texHeight = TexHeight;
  42
  43    glClear(GL_COLOR_BUFFER_BIT);
  44
  45    glMatrixMode(GL_PROJECTION);
  46    glLoadIdentity();
  47    glOrtho(0, WinWidth, 0, WinHeight, -1, 1);
  48    glMatrixMode(GL_MODELVIEW);
  49    glLoadIdentity();
  50
  51    glColor3f(1,1,1);
  52
  53    y = WinHeight - 300;
  54    x = 4;
  55
  56    for (bias = -1; bias < 11; bias++) {
  57
  58       if (ScaleQuads) {
  59          if (bias > 0) {
  60             if (texWidth == 1 && texHeight == 1)
  61                break;
  62             texWidth = TexWidth >> bias;
  63             texHeight = TexHeight >> bias;
  64             if (texWidth < 1)
  65                texWidth = 1;
  66             if (texHeight < 1)
  67                texHeight = 1;
  68          }
  69          glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, 0.0);
  70       }
  71       else {
  72          glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, bias);
  73       }
  74
  75       glRasterPos2f(x, y + TexHeight + 5);
  76       if (ScaleQuads)
  77          sprintf(str, "Texture Level %d: %d x %d",
  78                  (bias < 0 ? 0 : bias),
  79                  texWidth, texHeight);
  80       else
  81          sprintf(str, "Texture LOD Bias = %d", bias);
  82       PrintString(str);
  83
  84       glPushMatrix();
  85       glTranslatef(x, y, 0);
  86
  87       glEnable(GL_TEXTURE_2D);
  88
  89       glBegin(GL_POLYGON);
  90       glTexCoord2f(0, 0);  glVertex2f(0, 0);
  91       glTexCoord2f(1, 0);  glVertex2f(texWidth, 0);
  92       glTexCoord2f(1, 1);  glVertex2f(texWidth, texHeight);
  93       glTexCoord2f(0, 1);  glVertex2f(0, texHeight);
  94       glEnd();
  95
  96       glPopMatrix();
  97
  98       glDisable(GL_TEXTURE_2D);
  99
 100       x += TexWidth + 4;
 101       if (x >= WinWidth) {
 102          x = 4;
 103          y -= 300;
 104       }
 105    }
 106
 107    glutSwapBuffers();
 108 }
 109
 110
 111 static void
 112 Reshape(int width, int height)
 113 {
 114    WinWidth = width;
 115    WinHeight = height;
 116    glViewport(0, 0, width, height);
 117 }
 118
 119
 120 static void
 121 Key(unsigned char key, int x, int y)
 122 {
 123    (void) x;
 124    (void) y;
 125    switch (key) {
 126       case 'b':
 127          Bias -= 10;
 128          break;
 129       case 'B':
 130          Bias += 10;
 131          break;
 132       case '0':
 133       case '1':
 134       case '2':
 135       case '3':
 136       case '4':
 137       case '5':
 138       case '6':
 139       case '7':
 140       case '8':
 141       case '9':
 142          Bias = 100.0 * (key - '0');
 143          break;
 144       case 's':
 145          ScaleQuads = !ScaleQuads;
 146          break;
 147       case 27:
 148          exit(0);
 149          break;
 150    }
 151    glutPostRedisplay();
 152 }
 153
 154
 155 static void
 156 Init(void)
 157 {
 158    GLfloat maxBias;
 159
 160    if (!glutExtensionSupported("GL_EXT_texture_lod_bias")) {
 161       printf("Sorry, GL_EXT_texture_lod_bias not supported by this renderer.\n");
 162       exit(1);
 163    }
 164
 165    if (!glutExtensionSupported("GL_SGIS_generate_mipmap")) {
 166       printf("Sorry, GL_SGIS_generate_mipmap not supported by this renderer.\n");
 167       exit(1);
 168    }
 169
 170    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 171
 172    if (1) {
 173       /* test auto mipmap generation */
 174       GLint width, height, i;
 175       GLenum format;
 176       GLubyte *image = LoadRGBImage(TEXTURE_FILE, &width, &height, &format);
 177       if (!image) {
 178          printf("Error: could not load texture image %s\n", TEXTURE_FILE);
 179          exit(1);
 180       }
 181       /* resize to TexWidth x TexHeight */
 182       if (width != TexWidth || height != TexHeight) {
 183          GLubyte *newImage = malloc(TexWidth * TexHeight * 4);
 184          gluScaleImage(format, width, height, GL_UNSIGNED_BYTE, image,
 185                        TexWidth, TexHeight, GL_UNSIGNED_BYTE, newImage);
 186          free(image);
 187          image = newImage;
 188       }
 189       printf("Using GL_SGIS_generate_mipmap\n");
 190       glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
 191       glTexImage2D(GL_TEXTURE_2D, 0, format, TexWidth, TexHeight, 0,
 192                    format, GL_UNSIGNED_BYTE, image);
 193       free(image);
 194
 195       /* make sure mipmap was really generated correctly */
 196       width = TexWidth;
 197       height = TexHeight;
 198       for (i = 0; i < 9; i++) {
 199          GLint w, h;
 200          glGetTexLevelParameteriv(GL_TEXTURE_2D, i, GL_TEXTURE_WIDTH, &w);
 201          glGetTexLevelParameteriv(GL_TEXTURE_2D, i, GL_TEXTURE_HEIGHT, &h);
 202          printf("Level %d size: %d x %d\n", i, w, h);
 203          assert(w == width);
 204          assert(h == height);
 205          width /= 2;
 206          height /= 2;
 207       }
 208    }
 209    else {
 210       if (LoadRGBMipmaps(TEXTURE_FILE, GL_RGB)) {
 211          printf("Using gluBuildMipmaps()\n");
 212       }
 213       else {
 214          printf("Error: could not load texture image %s\n", TEXTURE_FILE);
 215          exit(1);
 216       }
 217    }
 218
 219
 220    /* mipmapping required for this extension */
 221    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
 222    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 223    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 224
 225    glGetFloatv(GL_MAX_TEXTURE_LOD_BIAS_EXT, &maxBias);
 226
 227    printf("GL_RENDERER: %s\n", (char*) glGetString(GL_RENDERER));
 228    printf("LOD bias range: [%g, %g]\n", -maxBias, maxBias);
 229
 230    printf("Press 's' to toggle quad scaling\n");
 231 }
 232
 233
 234 int
 235 main(int argc, char *argv[])
 236 {
 237    glutInit(&argc, argv);
 238    glutInitWindowPosition(0, 0);
 239    glutInitWindowSize(WinWidth, WinHeight);
 240    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 241    glutCreateWindow(argv[0]);
 242    glutReshapeFunc(Reshape);
 243    glutKeyboardFunc(Key);
 244    glutDisplayFunc(Display);
 245    Init();
 246    glutMainLoop();
 247    return 0;
 248 }