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Diffstat (limited to 'progs/demos/dissolve.c')
-rw-r--r-- | progs/demos/dissolve.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/progs/demos/dissolve.c b/progs/demos/dissolve.c new file mode 100644 index 00000000000..f1589a4e413 --- /dev/null +++ b/progs/demos/dissolve.c @@ -0,0 +1,158 @@ +/** + * Dissolve between two images using randomized stencil buffer + * and varying stencil ref. + * + * Brian Paul + * 29 Jan 2010 + */ + + +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <GL/glut.h> +#include "readtex.h" + +#define FILE1 "../images/bw.rgb" +#define FILE2 "../images/arch.rgb" + + +static int Win; +static int WinWidth = 400, WinHeight = 400; +static GLboolean Anim = GL_TRUE; + +static int ImgWidth[2], ImgHeight[2]; +static GLenum ImgFormat[2]; +static GLubyte *Image[2]; +static GLfloat ScaleX[2], ScaleY[2]; + +static GLubyte StencilRef = 0; + + +static void +Idle(void) +{ + StencilRef = (GLint) (glutGet(GLUT_ELAPSED_TIME) / 10); + glutPostRedisplay(); +} + + +static void +RandomizeStencilBuffer(void) +{ + GLubyte *b = malloc(WinWidth * WinHeight); + int i; + for (i = 0; i < WinWidth * WinHeight; i++) { + b[i] = rand() & 0xff; + } + + glStencilFunc(GL_ALWAYS, 0, ~0); + glPixelZoom(1.0, 1.0); + glDrawPixels(WinWidth, WinHeight, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, b); + + free(b); +} + + + +static void +Draw(void) +{ + glClear(GL_COLOR_BUFFER_BIT); + + glPixelZoom(ScaleX[0], ScaleY[0]); + glStencilFunc(GL_LESS, StencilRef, ~0); + glDrawPixels(ImgWidth[0], ImgHeight[0], ImgFormat[0], GL_UNSIGNED_BYTE, Image[0]); + + glPixelZoom(ScaleX[1], ScaleY[1]); + glStencilFunc(GL_GEQUAL, StencilRef, ~0); + glDrawPixels(ImgWidth[1], ImgHeight[1], ImgFormat[1], GL_UNSIGNED_BYTE, Image[1]); + + glutSwapBuffers(); +} + + +static void +Reshape(int width, int height) +{ + WinWidth = width; + WinHeight = height; + glViewport(0, 0, width, height); + glMatrixMode(GL_PROJECTION); + glLoadIdentity(); + glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0); + glMatrixMode(GL_MODELVIEW); + glLoadIdentity(); + glTranslatef(0.0, 0.0, -15.0); + + RandomizeStencilBuffer(); + + ScaleX[0] = (float) width / ImgWidth[0]; + ScaleY[0] = (float) height / ImgHeight[0]; + + ScaleX[1] = (float) width / ImgWidth[1]; + ScaleY[1] = (float) height / ImgHeight[1]; +} + + +static void +Key(unsigned char key, int x, int y) +{ + (void) x; + (void) y; + switch (key) { + case 'a': + Anim = !Anim; + if (Anim) + glutIdleFunc(Idle); + else + glutIdleFunc(NULL); + break; + case 27: + glutDestroyWindow(Win); + exit(0); + break; + } + glutPostRedisplay(); +} + + + +static void +Init(void) +{ + Image[0] = LoadRGBImage(FILE1, &ImgWidth[0], &ImgHeight[0], &ImgFormat[0]); + if (!Image[0]) { + printf("Couldn't read %s\n", FILE1); + exit(0); + } + + Image[1] = LoadRGBImage(FILE2, &ImgWidth[1], &ImgHeight[1], &ImgFormat[1]); + if (!Image[1]) { + printf("Couldn't read %s\n", FILE1); + exit(0); + } + + glEnable(GL_STENCIL_TEST); + glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP); + + glPixelStorei(GL_UNPACK_ALIGNMENT, 1); +} + + +int +main(int argc, char *argv[]) +{ + glutInit(&argc, argv); + glutInitWindowSize(WinWidth, WinHeight); + glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL); + Win = glutCreateWindow(argv[0]); + glutReshapeFunc(Reshape); + glutKeyboardFunc(Key); + glutDisplayFunc(Draw); + if (Anim) + glutIdleFunc(Idle); + Init(); + glutMainLoop(); + return 0; +} |