diff options
Diffstat (limited to 'progs/demos/showbuffer.c')
| -rw-r--r-- | progs/demos/showbuffer.c | 192 |
1 files changed, 0 insertions, 192 deletions
diff --git a/progs/demos/showbuffer.c b/progs/demos/showbuffer.c deleted file mode 100644 index 17f84dc62bd..00000000000 --- a/progs/demos/showbuffer.c +++ /dev/null @@ -1,192 +0,0 @@ -/* showbuffer.c */ - - -/* - * Copy the depth buffer to the color buffer as a grayscale image. - * Useful for inspecting the depth buffer values. - * - * This program is in the public domain. - * - * Brian Paul November 4, 1998 - */ - - -#include <assert.h> -#include <stdlib.h> -#include <GL/gl.h> -#include "showbuffer.h" - - - -/* - * Copy the depth buffer values into the current color buffer as a - * grayscale image. - * Input: winWidth, winHeight - size of the window - * zBlack - the Z value which should map to black (usually 1) - * zWhite - the Z value which should map to white (usually 0) - */ -void -ShowDepthBuffer( GLsizei winWidth, GLsizei winHeight, - GLfloat zBlack, GLfloat zWhite ) -{ - GLfloat *depthValues; - - assert(zBlack >= 0.0); - assert(zBlack <= 1.0); - assert(zWhite >= 0.0); - assert(zWhite <= 1.0); - assert(zBlack != zWhite); - - glPixelStorei(GL_UNPACK_ALIGNMENT, 1); - glPixelStorei(GL_PACK_ALIGNMENT, 1); - - /* Read depth values */ - depthValues = (GLfloat *) malloc(winWidth * winHeight * sizeof(GLfloat)); - assert(depthValues); - glReadPixels(0, 0, winWidth, winHeight, GL_DEPTH_COMPONENT, - GL_FLOAT, depthValues); - - /* Map Z values from [zBlack, zWhite] to gray levels in [0, 1] */ - /* Not using glPixelTransfer() because it's broke on some systems! */ - if (zBlack != 0.0 || zWhite != 1.0) { - GLfloat scale = 1.0 / (zWhite - zBlack); - GLfloat bias = -zBlack * scale; - int n = winWidth * winHeight; - int i; - for (i = 0; i < n; i++) - depthValues[i] = depthValues[i] * scale + bias; - } - - /* save GL state */ - glPushAttrib(GL_CURRENT_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT | - GL_TRANSFORM_BIT | GL_VIEWPORT_BIT); - - /* setup raster pos for glDrawPixels */ - glMatrixMode(GL_PROJECTION); - glPushMatrix(); - glLoadIdentity(); - - glOrtho(0.0, (GLdouble) winWidth, 0.0, (GLdouble) winHeight, -1.0, 1.0); - glMatrixMode(GL_MODELVIEW); - glPushMatrix(); - glLoadIdentity(); - - glDisable(GL_STENCIL_TEST); - glDisable(GL_DEPTH_TEST); - glRasterPos2f(0, 0); - - glDrawPixels(winWidth, winHeight, GL_LUMINANCE, GL_FLOAT, depthValues); - - glPopMatrix(); - glMatrixMode(GL_PROJECTION); - glPopMatrix(); - free(depthValues); - - glPopAttrib(); -} - - - - -/* - * Copy the alpha channel values into the current color buffer as a - * grayscale image. - * Input: winWidth, winHeight - size of the window - */ -void -ShowAlphaBuffer( GLsizei winWidth, GLsizei winHeight ) -{ - GLubyte *alphaValues; - - glPixelStorei(GL_UNPACK_ALIGNMENT, 1); - glPixelStorei(GL_PACK_ALIGNMENT, 1); - - /* Read alpha values */ - alphaValues = (GLubyte *) malloc(winWidth * winHeight * sizeof(GLubyte)); - assert(alphaValues); - glReadPixels(0, 0, winWidth, winHeight, GL_ALPHA, GL_UNSIGNED_BYTE, alphaValues); - - /* save GL state */ - glPushAttrib(GL_CURRENT_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL | - GL_TRANSFORM_BIT | GL_VIEWPORT_BIT); - - /* setup raster pos for glDrawPixels */ - glMatrixMode(GL_PROJECTION); - glPushMatrix(); - glLoadIdentity(); - - glOrtho(0.0, (GLdouble) winWidth, 0.0, (GLdouble) winHeight, -1.0, 1.0); - glMatrixMode(GL_MODELVIEW); - glPushMatrix(); - glLoadIdentity(); - - glDisable(GL_STENCIL_TEST); - glDisable(GL_DEPTH_TEST); - glRasterPos2f(0, 0); - - glDrawPixels(winWidth, winHeight, GL_LUMINANCE, GL_UNSIGNED_BYTE, alphaValues); - - glPopMatrix(); - glMatrixMode(GL_PROJECTION); - glPopMatrix(); - free(alphaValues); - - glPopAttrib(); -} - - - -/* - * Copy the stencil buffer values into the current color buffer as a - * grayscale image. - * Input: winWidth, winHeight - size of the window - * scale, bias - scale and bias to apply to stencil values for display - */ -void -ShowStencilBuffer( GLsizei winWidth, GLsizei winHeight, - GLfloat scale, GLfloat bias ) -{ - GLubyte *stencilValues; - - glPixelStorei(GL_UNPACK_ALIGNMENT, 1); - glPixelStorei(GL_PACK_ALIGNMENT, 1); - - /* Read stencil values */ - stencilValues = (GLubyte *) malloc(winWidth * winHeight * sizeof(GLubyte)); - assert(stencilValues); - glReadPixels(0, 0, winWidth, winHeight, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, stencilValues); - - /* save GL state */ - glPushAttrib(GL_CURRENT_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT | - GL_PIXEL_MODE_BIT | GL_TRANSFORM_BIT | GL_VIEWPORT_BIT); - - /* setup raster pos for glDrawPixels */ - glMatrixMode(GL_PROJECTION); - glPushMatrix(); - glLoadIdentity(); - - glOrtho(0.0, (GLdouble) winWidth, 0.0, (GLdouble) winHeight, -1.0, 1.0); - glMatrixMode(GL_MODELVIEW); - glPushMatrix(); - glLoadIdentity(); - - glDisable(GL_STENCIL_TEST); - glDisable(GL_DEPTH_TEST); - glRasterPos2f(0, 0); - - glPixelTransferf(GL_RED_SCALE, scale); - glPixelTransferf(GL_RED_BIAS, bias); - glPixelTransferf(GL_GREEN_SCALE, scale); - glPixelTransferf(GL_GREEN_BIAS, bias); - glPixelTransferf(GL_BLUE_SCALE, scale); - glPixelTransferf(GL_BLUE_BIAS, bias); - - glDrawPixels(winWidth, winHeight, GL_LUMINANCE, GL_UNSIGNED_BYTE, stencilValues); - - glPopMatrix(); - glMatrixMode(GL_PROJECTION); - glPopMatrix(); - free(stencilValues); - - glPopAttrib(); -} |