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-rw-r--r--progs/demos/shadowtex.c72
1 files changed, 50 insertions, 22 deletions
diff --git a/progs/demos/shadowtex.c b/progs/demos/shadowtex.c
index 634d0b6572..e87edcf071 100644
--- a/progs/demos/shadowtex.c
+++ b/progs/demos/shadowtex.c
@@ -67,6 +67,9 @@ static GLboolean NeedNewShadowMap = GL_FALSE;
static GLuint ShadowTexture, GrayTexture;
static GLuint ShadowFBO;
+static GLfloat lightModelview[16];
+static GLfloat lightProjection[16];
+
static GLboolean HaveFBO = GL_FALSE;
static GLboolean UseFBO = GL_FALSE;
static GLboolean HavePackedDepthStencil = GL_FALSE;
@@ -134,27 +137,56 @@ DrawScene(void)
}
-/*
- * Load the GL_TEXTURE matrix with the projection from the light
- * source's point of view.
+/**
+ * Calculate modelview and project matrices for the light
+ *
+ * Stores the results in \c lightProjection (projection matrix) and
+ * \c lightModelview (modelview matrix).
*/
static void
MakeShadowMatrix(const GLfloat lightPos[4], const GLfloat spotDir[3],
GLfloat spotAngle, GLfloat shadowNear, GLfloat shadowFar)
{
- GLfloat d;
-
- glMatrixMode(GL_TEXTURE);
+ /* compute frustum to enclose spot light cone */
+ const GLfloat d = shadowNear * tan(spotAngle);
+
+ glMatrixMode(GL_PROJECTION);
+ glPushMatrix();
glLoadIdentity();
- glTranslatef(0.5, 0.5, 0.5 + Bias);
- glScalef(0.5, 0.5, 0.5);
- d = shadowNear * tan(spotAngle);
glFrustum(-d, d, -d, d, shadowNear, shadowFar);
+ glGetFloatv(GL_PROJECTION_MATRIX, lightProjection);
+ glPopMatrix();
+
+ glMatrixMode(GL_MODELVIEW);
+ glPushMatrix();
+ glLoadIdentity();
gluLookAt(lightPos[0], lightPos[1], lightPos[2],
lightPos[0] + spotDir[0],
lightPos[1] + spotDir[1],
lightPos[2] + spotDir[2],
- 0, 1, 0);
+ 0.0, 1.0, 0.0);
+ glGetFloatv(GL_MODELVIEW_MATRIX, lightModelview);
+ glPopMatrix();
+}
+
+
+/**
+ * Load \c GL_TEXTURE matrix with light's MVP matrix.
+ */
+static void SetShadowTextureMatrix(void)
+{
+ static const GLfloat biasMatrix[16] = {
+ 0.5, 0.0, 0.0, 0.0,
+ 0.0, 0.5, 0.0, 0.0,
+ 0.0, 0.0, 0.5, 0.0,
+ 0.5, 0.5, 0.5, 1.0,
+ };
+
+ glMatrixMode(GL_TEXTURE);
+ glLoadMatrixf(biasMatrix);
+ glTranslatef(0.0, 0.0, Bias);
+ glMultMatrixf(lightProjection);
+ glMultMatrixf(lightModelview);
glMatrixMode(GL_MODELVIEW);
}
@@ -258,7 +290,6 @@ RenderShadowMap(void)
{
GLenum depthFormat; /* GL_DEPTH_COMPONENT or GL_DEPTH_STENCIL_EXT */
GLenum depthType; /* GL_UNSIGNED_INT_24_8_EXT or GL_UNSIGNED_INT */
- float d;
if (WindowWidth >= 1024 && WindowHeight >= 1024) {
ShadowTexWidth = ShadowTexHeight = 1024;
@@ -283,17 +314,11 @@ RenderShadowMap(void)
depthType = GL_UNSIGNED_INT;
}
- /* compute frustum to enclose spot light cone */
- d = ShadowNear * tan(SpotAngle);
-
glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- glFrustum(-d, d, -d, d, ShadowNear, ShadowFar);
+ glLoadMatrixf(lightProjection);
+
glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
- gluLookAt(LightPos[0], LightPos[1], LightPos[2], /* from */
- 0, 0, 0, /* target */
- 0, 1, 0); /* up */
+ glLoadMatrixf(lightModelview);
if (UseFBO) {
GLenum fbo_status;
@@ -418,6 +443,7 @@ Display(void)
LightPos, SpotDir);
if (NeedNewShadowMap) {
+ MakeShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
RenderShadowMap();
NeedNewShadowMap = GL_FALSE;
}
@@ -458,7 +484,8 @@ Display(void)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_NONE);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
- MakeShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
+
+ SetShadowTextureMatrix();
EnableIdentityTexgen();
}
else if (DisplayMode == SHOW_DISTANCE) {
@@ -476,7 +503,8 @@ Display(void)
GL_COMPARE_R_TO_TEXTURE_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glEnable(GL_TEXTURE_2D);
- MakeShadowMatrix(LightPos, SpotDir, SpotAngle, ShadowNear, ShadowFar);
+
+ SetShadowTextureMatrix();
EnableIdentityTexgen();
}