117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
/*
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* Test glRead/DrawPixels for GL_DEPTH_COMPONENT, with pixelzoom.
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*
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* Brian Paul
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* 23 August 2003
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#define GL_GLEXT_PROTOTYPES
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#include <GL/glut.h>
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static GLint WinWidth = 500, WinHeight = 500;
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static void Display(void)
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{
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GLfloat depth[100 * 100];
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GLfloat depth2[400 * 400];
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GLfloat min, max;
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int i;
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glClearColor(0.5, 0.5, 0.5, 0);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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/* draw a sphere */
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glViewport(0, 0, 100, 100);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-1, 1, -1, 1, -1, 0); /* clip away back half of sphere */
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glutSolidSphere(1.0, 20, 10);
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/* read the depth image */
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glReadPixels(0, 0, 100, 100, GL_DEPTH_COMPONENT, GL_FLOAT, depth);
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min = max = depth[0];
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for (i = 1; i < 100 * 100; i++) {
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if (depth[i] < min)
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min = depth[i];
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if (depth[i] > max)
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max = depth[i];
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}
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printf("Depth value range: [%f, %f]\n", min, max);
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/* draw depth image with scaling (into z buffer) */
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glPixelZoom(4.0, 4.0);
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glWindowPos2i(100, 0);
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glDrawPixels(100, 100, GL_DEPTH_COMPONENT, GL_FLOAT, depth);
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/* read back scaled depth image */
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glReadPixels(100, 0, 400, 400, GL_DEPTH_COMPONENT, GL_FLOAT, depth2);
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/* draw as luminance */
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glPixelZoom(1.0, 1.0);
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glDrawPixels(400, 400, GL_LUMINANCE, GL_FLOAT, depth2);
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glutSwapBuffers();
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}
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static void Reshape(int width, int height)
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{
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WinWidth = width;
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WinHeight = height;
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glViewport(0, 0, width, height);
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}
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static void Key(unsigned char key, int x, int y)
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{
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(void) x;
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(void) y;
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switch (key) {
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case 27:
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exit(0);
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break;
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}
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glutPostRedisplay();
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}
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static void Init(void)
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{
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const GLfloat blue[4] = {.1, .1, 1.0, 0.0};
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const GLfloat gray[4] = {0.2, 0.2, 0.2, 1.0};
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const GLfloat white[4] = {1.0, 1.0, 1.0, 1.0};
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const GLfloat pos[4] = {0, 0, 10, 0};
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printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
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printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
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glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, blue);
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glLightfv(GL_LIGHT0, GL_AMBIENT, gray);
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glLightfv(GL_LIGHT0, GL_DIFFUSE, white);
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glLightfv(GL_LIGHT0, GL_POSITION, pos);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glEnable(GL_DEPTH_TEST);
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}
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int main(int argc, char *argv[])
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{
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glutInit(&argc, argv);
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(WinWidth, WinHeight);
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glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
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glutCreateWindow(argv[0]);
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glutReshapeFunc(Reshape);
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glutKeyboardFunc(Key);
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glutDisplayFunc(Display);
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Init();
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glutMainLoop();
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return 0;
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}
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