diff options
Diffstat (limited to 'progs/demos/copypix.c')
| -rw-r--r-- | progs/demos/copypix.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/progs/demos/copypix.c b/progs/demos/copypix.c new file mode 100644 index 00000000000..15001e851be --- /dev/null +++ b/progs/demos/copypix.c @@ -0,0 +1,248 @@ +/** + * glCopyPixels test + * + * Brian Paul + * 14 Sep 2007 + */ + + +#define GL_GLEXT_PROTOTYPES + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <GL/glut.h> + +#include "readtex.h" + +#define IMAGE_FILE "../images/arch.rgb" + +static int ImgWidth, ImgHeight; +static GLenum ImgFormat; +static GLubyte *Image = NULL; + +static int WinWidth = 800, WinHeight = 800; +static int Xpos, Ypos; +static int Scissor = 0; +static float Xzoom, Yzoom; +static GLboolean DrawFront = GL_FALSE; +static GLboolean Dither = GL_TRUE; + + +static void Reset( void ) +{ + Xpos = Ypos = 20; + Scissor = 0; + Xzoom = Yzoom = 1.0; +} + + +static void Display( void ) +{ + const int dx = (WinWidth - ImgWidth) / 2; + const int dy = (WinHeight - ImgHeight) / 2; + + if (DrawFront) { + glDrawBuffer(GL_FRONT); + glReadBuffer(GL_FRONT); + } + else { + glDrawBuffer(GL_BACK); + glReadBuffer(GL_BACK); + } + + glClear( GL_COLOR_BUFFER_BIT ); + + /* draw original image */ + glWindowPos2iARB(dx, dy); + glDrawPixels(ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image); + + if (Scissor) + glEnable(GL_SCISSOR_TEST); + + /* draw copy */ + glPixelZoom(Xzoom, Yzoom); + glWindowPos2iARB(Xpos, Ypos); + glCopyPixels(dx, dy, ImgWidth, ImgHeight, GL_COLOR); + glPixelZoom(1, 1); + + glDisable(GL_SCISSOR_TEST); + + if (DrawFront) + glFinish(); + else + glutSwapBuffers(); +} + + +static void Reshape( int width, int height ) +{ + WinWidth = width; + WinHeight = height; + + glViewport( 0, 0, width, height ); + glMatrixMode( GL_PROJECTION ); + glLoadIdentity(); + glOrtho( 0.0, width, 0.0, height, 0.0, 2.0 ); + glMatrixMode( GL_MODELVIEW ); + glLoadIdentity(); + + glScissor(width/4, height/4, width/2, height/2); +} + + +static void Key( unsigned char key, int x, int y ) +{ + (void) x; + (void) y; + switch (key) { + case ' ': + Reset(); + break; + case 'd': + Dither = !Dither; + if (Dither) + glEnable(GL_DITHER); + else + glDisable(GL_DITHER); + break; + case 's': + Scissor = !Scissor; + break; + case 'x': + Xzoom -= 0.1; + break; + case 'X': + Xzoom += 0.1; + break; + case 'y': + Yzoom -= 0.1; + break; + case 'Y': + Yzoom += 0.1; + break; + case 'f': + DrawFront = !DrawFront; + printf("glDrawBuffer(%s)\n", DrawFront ? "GL_FRONT" : "GL_BACK"); + break; + case 27: + exit(0); + break; + } + glutPostRedisplay(); +} + + +static void SpecialKey( int key, int x, int y ) +{ + const int step = (glutGetModifiers() & GLUT_ACTIVE_SHIFT) ? 10 : 1; + (void) x; + (void) y; + switch (key) { + case GLUT_KEY_UP: + Ypos += step; + break; + case GLUT_KEY_DOWN: + Ypos -= step; + break; + case GLUT_KEY_LEFT: + Xpos -= step; + break; + case GLUT_KEY_RIGHT: + Xpos += step; + break; + } + glutPostRedisplay(); +} + + +static void Init( GLboolean ciMode, const char *filename ) +{ + printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); + printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); + + Image = LoadRGBImage( filename, &ImgWidth, &ImgHeight, &ImgFormat ); + if (!Image) { + printf("Couldn't read %s\n", filename); + exit(0); + } + + if (ciMode) { + /* Convert RGB image to grayscale */ + GLubyte *indexImage = (GLubyte *) malloc( ImgWidth * ImgHeight ); + GLint i; + for (i=0; i<ImgWidth*ImgHeight; i++) { + int gray = Image[i*3] + Image[i*3+1] + Image[i*3+2]; + indexImage[i] = gray / 3; + } + free(Image); + Image = indexImage; + ImgFormat = GL_COLOR_INDEX; + + for (i=0;i<255;i++) { + float g = i / 255.0; + glutSetColor(i, g, g, g); + } + } + + printf("Loaded %d by %d image\n", ImgWidth, ImgHeight ); + + glPixelStorei(GL_UNPACK_ALIGNMENT, 1); + glPixelStorei(GL_UNPACK_ROW_LENGTH, ImgWidth); + + Reset(); +} + + +static void Usage(void) +{ + printf("Keys:\n"); + printf(" SPACE Reset Parameters\n"); + printf(" Up/Down Move image up/down (SHIFT for large step)\n"); + printf(" Left/Right Move image left/right (SHIFT for large step)\n"); + printf(" x Decrease X-axis PixelZoom\n"); + printf(" X Increase X-axis PixelZoom\n"); + printf(" y Decrease Y-axis PixelZoom\n"); + printf(" Y Increase Y-axis PixelZoom\n"); + printf(" s Toggle GL_SCISSOR_TEST\n"); + printf(" f Toggle front/back buffer drawing\n"); + printf(" ESC Exit\n"); +} + + +int main( int argc, char *argv[] ) +{ + GLboolean ciMode = GL_FALSE; + const char *filename = IMAGE_FILE; + int i = 1; + + if (argc > i && strcmp(argv[i], "-ci")==0) { + ciMode = GL_TRUE; + i++; + } + if (argc > i) { + filename = argv[i]; + } + + glutInit( &argc, argv ); + glutInitWindowPosition( 0, 0 ); + glutInitWindowSize( WinWidth, WinHeight ); + + if (ciMode) + glutInitDisplayMode( GLUT_INDEX | GLUT_DOUBLE ); + else + glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE); + + glutCreateWindow(argv[0]); + + Init(ciMode, filename); + Usage(); + + glutReshapeFunc( Reshape ); + glutKeyboardFunc( Key ); + glutSpecialFunc( SpecialKey ); + glutDisplayFunc( Display ); + + glutMainLoop(); + return 0; +} |