progs/tests/blendxor.c

   1 /**
   2  * Test XOR emulation with blending.
   3  *
   4  */
   5
   6 #define GL_GLEXT_PROTOTYPES
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <math.h>
  10 #include <GL/glut.h>
  11 #include "readtex.c"
  12
  13 #define IMAGE_FILE "../images/arch.rgb"
  14
  15 static int ImgWidth, ImgHeight;
  16 static GLenum ImgFormat;
  17 static GLubyte *Image = NULL;
  18
  19 static int Win;
  20 static int Width = 600, Height = 600;
  21
  22 struct rect
  23 {
  24    int x0, y0, x1, y1;
  25 };
  26
  27 static struct rect OldRect, NewRect;
  28
  29 static GLboolean ButtonDown = GL_FALSE;
  30 static GLboolean LogicOp = 0*GL_TRUE;
  31
  32
  33 static const GLfloat red[4] = {1.0, 0.2, 0.2, 1.0};
  34 static const GLfloat green[4] = {0.2, 1.0, 0.2, 1.0};
  35 static const GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0};
  36
  37
  38 static void
  39 PrintString(const char *s)
  40 {
  41    while (*s) {
  42       glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
  43       s++;
  44    }
  45 }
  46
  47
  48 static void
  49 Draw(void)
  50 {
  51    glClear(GL_COLOR_BUFFER_BIT);
  52
  53    glWindowPos2i((Width - ImgWidth) / 2, (Height - ImgHeight) / 2);
  54    glDrawPixels(ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image);
  55
  56    /*
  57     * Draw 2D XOR rects
  58     */
  59    glColor3f(1, 1, 1);
  60
  61    glWindowPos2i(100, Height - 20);
  62    PrintString("XOR LogicOp:");
  63    glLogicOp(GL_XOR);
  64    glEnable(GL_COLOR_LOGIC_OP);
  65    glRecti(100, 30, 250, Height - 30);
  66    glDisable(GL_COLOR_LOGIC_OP);
  67
  68    glWindowPos2i(Width/2 + 10, Height - 20);
  69    PrintString("Invert Blending:");
  70    glBlendFunc(GL_ONE, GL_ONE);
  71    glBlendEquation(GL_FUNC_SUBTRACT);
  72    glEnable(GL_BLEND);
  73    glRecti(Width / 2, 30, Width / 2 + 150, Height - 30);
  74    glDisable(GL_BLEND);
  75
  76    glutSwapBuffers();
  77 }
  78
  79
  80 static void
  81 Reshape(int width, int height)
  82 {
  83    Width = width;
  84    Height = height;
  85    glViewport(0, 0, width, height);
  86    glMatrixMode(GL_PROJECTION);
  87    glLoadIdentity();
  88    glOrtho(0, Width, 0, Height, -1, 1);
  89    glMatrixMode(GL_MODELVIEW);
  90    glLoadIdentity();
  91 }
  92
  93
  94 static void
  95 Key(unsigned char key, int x, int y)
  96 {
  97    (void) x;
  98    (void) y;
  99    switch (key) {
 100    case 'b':
 101    case 'B':
 102       LogicOp = GL_FALSE;
 103       break;
 104    case 'l':
 105    case 'L':
 106       LogicOp = GL_TRUE;
 107       break;
 108    case 27:
 109       glutDestroyWindow(Win);
 110       exit(0);
 111       break;
 112    }
 113    glutPostRedisplay();
 114 }
 115
 116
 117 static void
 118 SpecialKey(int key, int x, int y)
 119 {
 120    (void) x;
 121    (void) y;
 122    switch (key) {
 123    case GLUT_KEY_UP:
 124       break;
 125    case GLUT_KEY_DOWN:
 126       break;
 127    case GLUT_KEY_LEFT:
 128       break;
 129    case GLUT_KEY_RIGHT:
 130       break;
 131    }
 132    glutPostRedisplay();
 133 }
 134
 135
 136 static void
 137 MouseMotion(int x, int y)
 138 {
 139    if (ButtonDown) {
 140       NewRect.x1 = x;
 141       NewRect.y1 = y;
 142       glutPostRedisplay();
 143    }
 144 }
 145
 146
 147 static void
 148 MouseButton(int button, int state, int x, int y)
 149 {
 150   if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
 151      ButtonDown = GL_TRUE;
 152      NewRect.x0 = NewRect.x1 = x;
 153      NewRect.y0 = NewRect.y1 = y;
 154      OldRect = NewRect;
 155   }
 156   else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
 157      ButtonDown = GL_FALSE;
 158   }
 159 }
 160
 161
 162 static void
 163 Init(void)
 164 {
 165    /*
 166     * Load image and scale if needed.
 167     */
 168    Image = LoadRGBImage(IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat);
 169    if (!Image) {
 170       printf("Couldn't read %s\n", IMAGE_FILE);
 171       exit(0);
 172    }
 173
 174    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 175    glPixelStorei(GL_PACK_ALIGNMENT, 1);
 176 }
 177
 178
 179 int
 180 main(int argc, char *argv[])
 181 {
 182    glutInit(&argc, argv);
 183    glutInitWindowSize(Width, Height);
 184    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 185    Win = glutCreateWindow(argv[0]);
 186    glutReshapeFunc(Reshape);
 187    glutKeyboardFunc(Key);
 188    glutSpecialFunc(SpecialKey);
 189    glutMotionFunc(MouseMotion);
 190    glutMouseFunc(MouseButton);
 191    glutDisplayFunc(Draw);
 192    Init();
 193    glutPostRedisplay();
 194    glutMainLoop();
 195    return 0;
 196 }