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Add support for shadow mapping with vertex and fragment programs
This commit is contained in:
Ian Romanick
parent
2260c245fd
commit
359c6eada7
1 changed files with 216 additions and 4 deletions
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@ -9,6 +9,7 @@
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* Added GL_EXT_packed_depth_stencil support on 15 March 2006.
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* Added GL_EXT_framebuffer_object support on 27 March 2006.
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* Removed old SGIX extension support on 5 April 2006.
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* Added vertex / fragment program support on 7 June 2007 (Ian Romanick).
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*
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* Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
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*
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@ -34,6 +35,7 @@
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include <GL/glut.h>
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#include "showbuffer.h"
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@ -70,8 +72,24 @@ static GLuint ShadowFBO;
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static GLfloat lightModelview[16];
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static GLfloat lightProjection[16];
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static GLuint vert_prog;
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static GLuint frag_progs[3];
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static GLuint curr_frag = 0;
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static GLuint max_frag = 1;
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#define NUM_FRAG_MODES 3
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static const char *FragProgNames[] = {
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"fixed-function",
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"program without \"OPTION ARB_fragment_program_shadow\"",
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"program with \"OPTION ARB_fragment_program_shadow\"",
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};
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static GLboolean HaveFBO = GL_FALSE;
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static GLboolean UseFBO = GL_FALSE;
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static GLboolean HaveVP = GL_FALSE;
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static GLboolean HaveFP = GL_FALSE;
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static GLboolean HaveFP_Shadow = GL_FALSE;
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static GLboolean UseVP = GL_FALSE;
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static GLboolean HavePackedDepthStencil = GL_FALSE;
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static GLboolean UsePackedDepthStencil = GL_FALSE;
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static GLboolean HaveEXTshadowFuncs = GL_FALSE;
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@ -94,6 +112,103 @@ static GLuint DisplayMode;
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#define MAT4_MUL(dest_vec, src_mat, src_vec) \
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"DP4 " dest_vec ".x, " src_mat "[0], " src_vec ";\n" \
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"DP4 " dest_vec ".y, " src_mat "[1], " src_vec ";\n" \
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"DP4 " dest_vec ".z, " src_mat "[2], " src_vec ";\n" \
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"DP4 " dest_vec ".w, " src_mat "[3], " src_vec ";\n"
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#define MAT3_MUL(dest_vec, src_mat, src_vec) \
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"DP3 " dest_vec ".x, " src_mat "[0], " src_vec ";\n" \
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"DP3 " dest_vec ".y, " src_mat "[1], " src_vec ";\n" \
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"DP3 " dest_vec ".z, " src_mat "[2], " src_vec ";\n"
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#define NORMALIZE(dest, src) \
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"DP3 " dest ".w, " src ", " src ";\n" \
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"RSQ " dest ".w, " dest ".w;\n" \
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"MUL " dest ", " src ", " dest ".w;\n"
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/**
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* Vertex program for shadow mapping.
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*/
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static const char vert_code[] =
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"!!ARBvp1.0\n"
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"ATTRIB iPos = vertex.position;\n"
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"ATTRIB iNorm = vertex.normal;\n"
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"PARAM mvinv[4] = { state.matrix.modelview.invtrans };\n"
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"PARAM mvp[4] = { state.matrix.mvp };\n"
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"PARAM mv[4] = { state.matrix.modelview };\n"
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"PARAM texmat[4] = { state.matrix.texture[0] };\n"
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"PARAM lightPos = state.light[0].position;\n"
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"PARAM ambientCol = state.lightprod[0].ambient;\n"
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"PARAM diffuseCol = state.lightprod[0].diffuse;\n"
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"TEMP n, lightVec;\n"
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"ALIAS V = lightVec;\n"
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"ALIAS NdotL = n;\n"
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"OUTPUT oPos = result.position;\n"
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"OUTPUT oColor = result.color;\n"
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"OUTPUT oTex = result.texcoord[0];\n"
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/* Transform the vertex to clip coordinates. */
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MAT4_MUL("oPos", "mvp", "iPos")
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/* Transform the vertex to eye coordinates. */
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MAT4_MUL("V", "mv", "iPos")
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/* Transform the vertex to projected light coordinates. */
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MAT4_MUL("oTex", "texmat", "iPos")
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/* Transform the normal to eye coordinates. */
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MAT3_MUL("n", "mvinv", "iNorm")
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/* Calculate the vector from the vertex to the light in eye
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* coordinates.
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*/
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"SUB lightVec, lightPos, V;\n"
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NORMALIZE("lightVec", "lightVec")
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/* Compute diffuse lighting coefficient.
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*/
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"DP3 NdotL.x, n, lightVec;\n"
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"MAX NdotL.x, NdotL.x, {0.0};\n"
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"MIN NdotL.x, NdotL.x, {1.0};\n"
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/* Accumulate color contributions.
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*/
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"MOV oColor, diffuseCol;\n"
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"MAD oColor.xyz, NdotL.x, diffuseCol, ambientCol;\n"
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"END\n"
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;
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static const char frag_code[] =
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"!!ARBfp1.0\n"
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"TEMP shadow, temp;\n"
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"TXP shadow, fragment.texcoord[0], texture[0], 2D;\n"
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"RCP temp.x, fragment.texcoord[0].w;\n"
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"MUL temp.x, temp.x, fragment.texcoord[0].z;\n"
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"SGE shadow, shadow.x, temp.x;\n"
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"MUL result.color.rgb, fragment.color, shadow.x;\n"
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"MOV result.color.a, fragment.color;\n"
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"END\n"
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;
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static const char frag_shadow_code[] =
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"!!ARBfp1.0\n"
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"OPTION ARB_fragment_program_shadow;\n"
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"TEMP shadow;\n"
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"TXP shadow, fragment.texcoord[0], texture[0], SHADOW2D;\n"
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"MUL result.color.rgb, fragment.color, shadow.x;\n"
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"MOV result.color.a, fragment.color.a;\n"
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"END\n"
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;
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static void
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DrawScene(void)
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{
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@ -501,17 +616,40 @@ Display(void)
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assert(DisplayMode == SHOW_SHADOWS);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB,
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GL_COMPARE_R_TO_TEXTURE_ARB);
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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if (curr_frag > 0) {
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glEnable(GL_FRAGMENT_PROGRAM_ARB);
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}
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else {
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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}
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glEnable(GL_TEXTURE_2D);
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SetShadowTextureMatrix();
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EnableIdentityTexgen();
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if (UseVP) {
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glEnable(GL_VERTEX_PROGRAM_ARB);
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}
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else {
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glEnable(GL_LIGHTING);
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EnableIdentityTexgen();
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}
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}
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DrawScene();
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DisableTexgen();
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glDisable(GL_TEXTURE_1D);
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if (UseVP) {
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glDisable(GL_VERTEX_PROGRAM_ARB);
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}
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else {
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DisableTexgen();
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glDisable(GL_LIGHTING);
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}
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if (curr_frag > 0) {
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glDisable(GL_FRAGMENT_PROGRAM_ARB);
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}
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glDisable(GL_TEXTURE_2D);
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}
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@ -583,6 +721,14 @@ Key(unsigned char key, int x, int y)
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case 'm':
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DisplayMode = SHOW_DEPTH_MAPPING;
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break;
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case 'M':
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curr_frag = (1 + curr_frag) % max_frag;
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printf("Using fragment %s\n", FragProgNames[curr_frag]);
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if (HaveFP) {
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glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, frag_progs[curr_frag]);
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}
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break;
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case 'n':
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case 's':
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case ' ':
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@ -612,6 +758,11 @@ Key(unsigned char key, int x, int y)
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NeedNewShadowMap = GL_TRUE;
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}
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break;
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case 'v':
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UseVP = !UseVP && HaveVP;
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printf("Using vertex %s mode.\n",
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UseVP ? "program" : "fixed-function");
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break;
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case 'z':
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Zrot -= step;
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break;
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@ -666,6 +817,42 @@ SpecialKey(int key, int x, int y)
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}
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/* A helper for finding errors in program strings */
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static int FindLine( const char *program, int position )
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{
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int i, line = 1;
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for (i = 0; i < position; i++) {
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if (program[i] == '\n')
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line++;
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}
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return line;
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}
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static GLuint
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compile_program(GLenum target, const char *code)
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{
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GLuint p;
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GLint errorPos;
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glGenProgramsARB(1, & p);
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glBindProgramARB(target, p);
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glProgramStringARB(target, GL_PROGRAM_FORMAT_ASCII_ARB,
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strlen(code), code);
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glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorPos);
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if (glGetError() != GL_NO_ERROR || errorPos != -1) {
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int l = FindLine(code, errorPos);
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printf("Fragment Program Error (pos=%d line=%d): %s\n", errorPos, l,
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(char *) glGetString(GL_PROGRAM_ERROR_STRING_ARB));
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exit(0);
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}
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glBindProgramARB(target, 0);
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return p;
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}
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static void
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Init(void)
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{
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@ -678,6 +865,10 @@ Init(void)
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}
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printf("Using GL_ARB_depth_texture and GL_ARB_shadow\n");
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HaveVP = glutExtensionSupported("GL_ARB_vertex_program");
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HaveFP = glutExtensionSupported("GL_ARB_fragment_program");
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HaveFP_Shadow = glutExtensionSupported("GL_ARB_fragment_program_shadow");
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HaveShadowAmbient = glutExtensionSupported("GL_ARB_shadow_ambient");
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if (HaveShadowAmbient) {
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printf("and GL_ARB_shadow_ambient\n");
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@ -744,6 +935,25 @@ Init(void)
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256, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, image);
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}
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if (HaveVP) {
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vert_prog = compile_program(GL_VERTEX_PROGRAM_ARB, vert_code);
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glBindProgramARB(GL_VERTEX_PROGRAM_ARB, vert_prog);
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}
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max_frag = 1;
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frag_progs[0] = 0;
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if (HaveFP) {
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frag_progs[1] = compile_program(GL_FRAGMENT_PROGRAM_ARB, frag_code);
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max_frag = 2;
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}
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if (HaveFP && HaveFP_Shadow) {
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frag_progs[2] = compile_program(GL_FRAGMENT_PROGRAM_ARB,
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frag_shadow_code);
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max_frag = 3;
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}
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glEnable(GL_DEPTH_TEST);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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@ -762,6 +972,8 @@ PrintHelp(void)
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printf(" f = toggle nearest/bilinear texture filtering\n");
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printf(" b/B = decrease/increase shadow map Z bias\n");
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printf(" p = toggle use of packed depth/stencil\n");
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printf(" M = cycle through fragment program modes\n");
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printf(" v = toggle vertex program modes\n");
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printf(" cursor keys = rotate scene\n");
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printf(" <shift> + cursor keys = rotate light source\n");
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if (HaveEXTshadowFuncs)
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