/* * Test glRead/DrawPixels for GL_DEPTH_COMPONENT, with pixelzoom. * * Brian Paul * 23 August 2003 */ #include <stdio.h> #include <stdlib.h> #include <math.h> #include <GL/glew.h> #include <GL/glut.h> static GLint WinWidth = 500, WinHeight = 500; static GLboolean Invert = GL_FALSE; static GLboolean TestPacking = GL_FALSE; static GLboolean TestList = GL_FALSE; static void Display(void) { GLfloat depth[100 * 100 * 2]; GLfloat depth2[400 * 400]; /* *2 to test pixelstore stuff */ GLuint list; GLenum depthType = GL_FLOAT; glClearColor(0.5, 0.5, 0.5, 1.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glEnable(GL_DEPTH_TEST); /* draw a sphere */ glViewport(0, 0, 100, 100); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-1, 1, -1, 1, -1, 0); /* clip away back half of sphere */ glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glutSolidSphere(1.0, 20, 10); if (TestPacking) { glPixelStorei(GL_PACK_ROW_LENGTH, 120); glPixelStorei(GL_PACK_SKIP_PIXELS, 5); } /* read the depth image */ glReadPixels(0, 0, 100, 100, GL_DEPTH_COMPONENT, depthType, depth); if (depthType == GL_FLOAT) { GLfloat min, max; int i; min = max = depth[0]; for (i = 1; i < 100 * 100; i++) { if (depth[i] < min) min = depth[i]; if (depth[i] > max) max = depth[i]; } printf("Depth value range: [%f, %f]\n", min, max); } /* Draw the Z image as luminance above original rendering */ glWindowPos2i(0, 100); glDrawPixels(100, 100, GL_LUMINANCE, depthType, depth); if (TestPacking) { glPixelStorei(GL_PACK_ROW_LENGTH, 0); glPixelStorei(GL_PACK_SKIP_PIXELS, 0); glPixelStorei(GL_UNPACK_ROW_LENGTH, 120); glPixelStorei(GL_UNPACK_SKIP_PIXELS, 5); } /* draw depth image with scaling (into z buffer) */ glPixelZoom(4.0, 4.0); glColor4f(1, 0, 0, 0); glWindowPos2i(100, 0); if (Invert) { glPixelTransferf(GL_DEPTH_SCALE, -1.0); glPixelTransferf(GL_DEPTH_BIAS, 1.0); } if (TestList) { list = glGenLists(1); glNewList(list, GL_COMPILE); glDrawPixels(100, 100, GL_DEPTH_COMPONENT, depthType, depth); glEndList(); glCallList(list); glDeleteLists(list, 1); } else { glDrawPixels(100, 100, GL_DEPTH_COMPONENT, depthType, depth); } if (Invert) { glPixelTransferf(GL_DEPTH_SCALE, 1.0); glPixelTransferf(GL_DEPTH_BIAS, 0.0); } if (TestPacking) { glPixelStorei(GL_UNPACK_ROW_LENGTH, 0); glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0); } glDisable(GL_DEPTH_TEST); /* read back scaled depth image */ glReadPixels(100, 0, 400, 400, GL_DEPTH_COMPONENT, GL_FLOAT, depth2); /* debug */ if (0) { int i; float *z = depth2 + 400 * 200; printf("z at y=200:\n"); for (i = 0; i < 400; i++) { printf("%5.3f ", z[i]); if ((i + 1) % 12 == 0) printf("\n"); } } /* draw as luminance */ glPixelZoom(1.0, 1.0); glWindowPos2i(100, 0); glDrawPixels(400, 400, GL_LUMINANCE, GL_FLOAT, depth2); glutSwapBuffers(); } static void Reshape(int width, int height) { WinWidth = width; WinHeight = height; glViewport(0, 0, width, height); } static void Key(unsigned char key, int x, int y) { (void) x; (void) y; switch (key) { case 'i': Invert = !Invert; break; case 'p': TestPacking = !TestPacking; printf("Test pixel pack/unpack: %d\n", TestPacking); break; case 'l': TestList = !TestList; printf("Test dlist: %d\n", TestList); break; case 27: exit(0); break; } glutPostRedisplay(); } static void Init(void) { const GLfloat blue[4] = {.1, .1, 1.0, 1.0}; const GLfloat gray[4] = {0.2, 0.2, 0.2, 1.0}; const GLfloat white[4] = {1.0, 1.0, 1.0, 1.0}; const GLfloat pos[4] = {0, 0, 10, 0}; printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, blue); glLightfv(GL_LIGHT0, GL_AMBIENT, gray); glLightfv(GL_LIGHT0, GL_DIFFUSE, white); glLightfv(GL_LIGHT0, GL_POSITION, pos); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowPosition(0, 0); glutInitWindowSize(WinWidth, WinHeight); glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE); glutCreateWindow(argv[0]); glewInit(); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutDisplayFunc(Display); Init(); glutMainLoop(); return 0; }