src/tests/blendxor.c

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