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authormarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
committermarha <marha@users.sourceforge.net>2009-10-08 13:15:52 +0000
commita0c4815433ccd57322f4f7703ca35e9ccfa59250 (patch)
treef5213802ec12adb86ec3136001c1c29fe5343700 /mesalib/progs/util/showbuffer.c
parentc73dc01b6de45612b24dc2dd34fba24d81ebf46c (diff)
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Added MesaLib-7.6
Diffstat (limited to 'mesalib/progs/util/showbuffer.c')
-rw-r--r--mesalib/progs/util/showbuffer.c198
1 files changed, 198 insertions, 0 deletions
diff --git a/mesalib/progs/util/showbuffer.c b/mesalib/progs/util/showbuffer.c
new file mode 100644
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--- /dev/null
+++ b/mesalib/progs/util/showbuffer.c
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+/* 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();
+
+ glViewport(0, 0, winWidth, winHeight);
+
+ 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();
+
+ glViewport(0, 0, winWidth, winHeight);
+
+ 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();
+
+ glViewport(0, 0, winWidth, winHeight);
+
+ 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();
+}