src/fp/tri-tex.c

   1
   2 #include <assert.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <glad/glad.h>
   7 #include "glut_wrap.h"
   8
   9 #include "readtex.c"
  10
  11
  12 #define TEXTURE_FILE DEMOS_DATA_DIR "girl.rgb"
  13
  14
  15
  16 static void Init( void )
  17 {
  18    static const char *modulate2D =
  19       "!!ARBfp1.0\n"
  20       "TEX result.color, fragment.color, texture[0], 2D; \n"
  21       "END"
  22       ;
  23    GLuint modulateProg;
  24    GLuint Texture;
  25
  26    if (!GLAD_GL_ARB_fragment_program) {
  27       printf("Error: GL_ARB_fragment_program not supported!\n");
  28       exit(1);
  29    }
  30    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
  31
  32    /* Setup the fragment program */
  33    glGenProgramsARB(1, &modulateProg);
  34    glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, modulateProg);
  35    glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  36                         strlen(modulate2D), (const GLubyte *)modulate2D);
  37
  38    printf("glGetError = 0x%x\n", (int) glGetError());
  39    printf("glError(GL_PROGRAM_ERROR_STRING_ARB) = %s\n",
  40           (char *) glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  41    assert(glIsProgramARB(modulateProg));
  42
  43    glEnable(GL_FRAGMENT_PROGRAM_ARB);
  44
  45    /* Load texture */
  46    glGenTextures(1, &Texture);
  47    glBindTexture(GL_TEXTURE_2D, Texture);
  48    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  49    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  50    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  51    if (!LoadRGBMipmaps(TEXTURE_FILE, GL_RGB)) {
  52       printf("Error: couldn't load texture image file %s\n", TEXTURE_FILE);
  53       exit(1);
  54    }
  55    /* XXX this enable shouldn't really be needed!!! */
  56    glEnable(GL_TEXTURE_2D);
  57
  58    glClearColor(.3, .3, .3, 0);
  59 }
  60
  61 static void Reshape(int width, int height)
  62 {
  63
  64     glViewport(0, 0, (GLint)width, (GLint)height);
  65
  66     glMatrixMode(GL_PROJECTION);
  67     glLoadIdentity();
  68     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  69     glMatrixMode(GL_MODELVIEW);
  70 }
  71
  72 static void Key(unsigned char key, int x, int y)
  73 {
  74
  75     switch (key) {
  76       case 27:
  77         exit(1);
  78       default:
  79         break;
  80     }
  81
  82     glutPostRedisplay();
  83 }
  84
  85 static void Draw(void)
  86 {
  87    glClear(GL_COLOR_BUFFER_BIT);
  88
  89    glBegin(GL_TRIANGLES);
  90    glColor3f(0,0,1);
  91 /*    glTexCoord2f(1, 0); */
  92    glVertex3f( 0.9, -0.9, -30.0);
  93    glColor3f(1,0,0);
  94 /*    glTexCoord2f(1, 1); */
  95    glVertex3f( 0.9,  0.9, -30.0);
  96    glColor3f(0,1,0);
  97 /*    glTexCoord2f(0, .5); */
  98    glVertex3f(-0.9,  0.0, -30.0);
  99    glEnd();
 100
 101    glFlush();
 102 }
 103
 104
 105 int main(int argc, char **argv)
 106 {
 107     GLenum type;
 108
 109     glutInit(&argc, argv);
 110
 111
 112
 113     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 114
 115     type = GLUT_RGB;
 116     type |= GLUT_SINGLE;
 117     glutInitDisplayMode(type);
 118
 119     if (glutCreateWindow("First Tri") == GL_FALSE) {
 120         exit(1);
 121     }
 122
 123     gladLoadGL();
 124
 125     Init();
 126
 127     glutReshapeFunc(Reshape);
 128     glutKeyboardFunc(Key);
 129     glutDisplayFunc(Draw);
 130     glutMainLoop();
 131         return 0;
 132 }