src/tests/floattex.c

   1 /*
   2  * Test floating point textures.
   3  * No actual rendering, yet.
   4  */
   5
   6
   7 #include <assert.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <math.h>
  11 #include <GL/glut.h>
  12 #include "extfuncs.h"
  13 #include "readtex.h"
  14 #include "shaderutil.h"
  15
  16
  17 static const char *TexFile = "../images/arch.rgb";
  18
  19 static const char *FragShaderText =
  20    "uniform sampler2D tex1; \n"
  21    "void main() \n"
  22    "{ \n"
  23    "   vec4 t = texture2D(tex1, gl_TexCoord[0].xy); \n"
  24    "   // convert from [-255,0] to [0,1] \n"
  25    "   gl_FragColor = t * (-1.0 / 255.0); \n"
  26    "} \n";
  27
  28 static const char *VertShaderText =
  29    "void main() \n"
  30    "{ \n"
  31    "   gl_TexCoord[0] = gl_MultiTexCoord0; \n"
  32    "   gl_Position = ftransform(); \n"
  33    "} \n";
  34
  35 static struct uniform_info Uniforms[] = {
  36    { "tex1",  1, GL_INT, { 0, 0, 0, 0 }, -1 },
  37    END_OF_UNIFORMS
  38 };
  39
  40
  41 static GLuint Program;
  42
  43
  44
  45 static GLboolean
  46 CheckError( int line )
  47 {
  48    GLenum error = glGetError();
  49    if (error) {
  50       char *err = (char *) gluErrorString( error );
  51       fprintf( stderr, "GL Error: %s at line %d\n", err, line );
  52       return GL_TRUE;
  53    }
  54    return GL_FALSE;
  55 }
  56
  57
  58 static void
  59 Draw(void)
  60 {
  61    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  62
  63    glPushMatrix();
  64
  65    glBegin(GL_POLYGON);
  66    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  67    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  68    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  69    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  70    glEnd();
  71
  72    glPopMatrix();
  73
  74    glutSwapBuffers();
  75 }
  76
  77
  78 static void
  79 Reshape(int width, int height)
  80 {
  81    glViewport(0, 0, width, height);
  82    glMatrixMode(GL_PROJECTION);
  83    glLoadIdentity();
  84    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  85    glMatrixMode(GL_MODELVIEW);
  86    glLoadIdentity();
  87    glTranslatef(0.0, 0.0, -8.0);
  88 }
  89
  90
  91 static void
  92 Key(unsigned char key, int x, int y)
  93 {
  94    (void) x;
  95    (void) y;
  96    switch (key) {
  97       case 27:
  98          exit(0);
  99          break;
 100    }
 101    glutPostRedisplay();
 102 }
 103
 104
 105
 106 static void
 107 InitTexture(void)
 108 {
 109    GLenum filter = GL_LINEAR;
 110    GLint imgWidth, imgHeight;
 111    GLenum imgFormat;
 112    GLubyte *image = NULL;
 113    GLfloat *ftex;
 114    GLint i, t;
 115
 116    image = LoadRGBImage(TexFile, &imgWidth, &imgHeight, &imgFormat);
 117    if (!image) {
 118       printf("Couldn't read %s\n", TexFile);
 119       exit(0);
 120    }
 121
 122    assert(imgFormat == GL_RGB);
 123
 124    ftex = (float *) malloc(imgWidth * imgHeight * 4 * sizeof(float));
 125    if (!ftex) {
 126       printf("out of memory\n");
 127       exit(0);
 128    }
 129
 130    /* convert ubytes to floats, negated */
 131    for (i = 0; i < imgWidth * imgHeight * 3; i++) {
 132       ftex[i] = -1.0f * image[i];
 133    }
 134
 135    glActiveTexture(GL_TEXTURE0);
 136    glBindTexture(GL_TEXTURE_2D, 42);
 137
 138    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F_ARB,
 139                 imgWidth, imgHeight, 0,
 140                 GL_RGB, GL_FLOAT, ftex);
 141
 142
 143    /* sanity checks */
 144    glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_RED_TYPE_ARB, &t);
 145    assert(t == GL_FLOAT);
 146    glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_GREEN_TYPE_ARB, &t);
 147    assert(t == GL_FLOAT);
 148    glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_BLUE_TYPE_ARB, &t);
 149    assert(t == GL_FLOAT);
 150    glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_ALPHA_TYPE_ARB, &t);
 151    assert(t == GL_FLOAT);
 152
 153    free(image);
 154    free(ftex);
 155
 156    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 157    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 158    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
 159    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
 160
 161 #if 0
 162    /* read back the texture and make sure values are correct */
 163    glGetTexImage(GL_TEXTURE_2D, 0, GL_RGBA, GL_FLOAT, tex2);
 164    CheckError(__LINE__);
 165    for (i = 0; i < 16; i++) {
 166       for (j = 0; j < 16; j++) {
 167          if (tex[i][j][0] != tex2[i][j][0] ||
 168              tex[i][j][1] != tex2[i][j][1] ||
 169              tex[i][j][2] != tex2[i][j][2] ||
 170              tex[i][j][3] != tex2[i][j][3]) {
 171             printf("tex[%d][%d] %g %g %g %g != tex2[%d][%d] %g %g %g %g\n",
 172                    i, j,
 173                    tex[i][j][0], tex[i][j][1], tex[i][j][2], tex[i][j][3],
 174                    i, j,
 175                    tex2[i][j][0], tex2[i][j][1], tex2[i][j][2], tex2[i][j][3]);
 176          }
 177       }
 178    }
 179 #endif
 180 }
 181
 182
 183 static GLuint
 184 CreateProgram(void)
 185 {
 186    GLuint fragShader, vertShader, program;
 187
 188    vertShader = CompileShaderText(GL_VERTEX_SHADER, VertShaderText);
 189    fragShader = CompileShaderText(GL_FRAGMENT_SHADER, FragShaderText);
 190    assert(vertShader);
 191    program = LinkShaders(vertShader, fragShader);
 192
 193    assert(program);
 194
 195    // InitUniforms(program, Uniforms);
 196
 197    return program;
 198 }
 199
 200
 201 static void
 202 Init(void)
 203 {
 204    glClearColor(0.25, 0.25, 0.25, 0.0);
 205
 206    GetExtensionFuncs();
 207
 208    if (!ShadersSupported()) {
 209       printf("Sorry, this test requires GLSL\n");
 210       exit(1);
 211    }
 212
 213    if (!glutExtensionSupported("GL_MESAX_texture_float")) {
 214       printf("Sorry, this test requires GL_MESAX_texture_float\n");
 215       exit(1);
 216    }
 217
 218    InitTexture();
 219
 220    Program = CreateProgram();
 221    glUseProgram_func(Program);
 222 }
 223
 224
 225 int
 226 main(int argc, char *argv[])
 227 {
 228    glutInit(&argc, argv);
 229    glutInitWindowPosition(0, 0);
 230    glutInitWindowSize(400, 400);
 231    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 232    glutCreateWindow(argv[0]);
 233    glutReshapeFunc(Reshape);
 234    glutKeyboardFunc(Key);
 235    glutDisplayFunc(Draw);
 236    Init();
 237    glutMainLoop();
 238    return 0;
 239 }