// This pass takes a photon buffer (computed above). It runs through each
// pixel in the buffer, treating the pixel as a photon position, and
// splatting the resulting photon into the specificed caustic map
// (using the viewing matrices for the specified light).
void CreateCausticMap( FrameBuffer *cMap, int lightNum )
{
/* setup the texture we'll draw to */
cMap->BindBuffer();
cMap->ClearBuffers();
SetLightMatrices( lightNum, cMap->GetAspectRatio() );
/* set some necessary GL state. */
glDisable( GL_CULL_FACE );
glDisable( GL_DEPTH_TEST );
/* the photon buffer vertex array already contains light-space coordinates! */
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
/* Draw the photons... */
glBindBuffer( GL_ARRAY_BUFFER, data->vbo->genericTraversalBuffer[0] ); // Buffer containing garbage... Needed b/c
glVertexPointer( 2, GL_SHORT, 0, BUFFER_OFFSET( 0 ) ); // OpenGL *requires* vertex positions, even
glEnableClientState( GL_VERTEX_ARRAY ); // if we read positions from a texture.
// Enable our shader, set up all the parameters we need to specify.
data->shader->caustic_SimplePhotonSplat->EnableShader();
data->shader->caustic_SimplePhotonSplat->BindAndEnableTexture( "photonPositions",
data->fbo->caustic_PhotonBuffer->GetColorTextureID(), GL_TEXTURE0, GL_TEXTURE_2D );
data->shader->caustic_SimplePhotonSplat->BindAndEnableTexture( "lightColor",
data->tex->spotlight->TextureID(), GL_TEXTURE1, GL_TEXTURE_2D );
data->shader->caustic_SimplePhotonSplat->SetParameter( "photonBufferResolution",
data->fbo->caustic_PhotonBuffer->GetWidth() );
data->shader->caustic_SimplePhotonSplat->SetParameter( "causticMapResolution",
cMap->GetWidth() );
data->shader->caustic_SimplePhotonSplat->SetParameter( "photonResolutionMultiplier",
sqr( cMap->GetWidth()/(float)data->fbo->caustic_PhotonBuffer->GetWidth() ) );
// OK. We enabled the shader, now start drawing.
glEnable(GL_BLEND); // We're drawing "splats" so enable blending
glBlendFuncSeparate(GL_ONE, GL_ONE, GL_ONE, GL_ONE); // in order to correctly combine their
glBlendEquation(GL_FUNC_ADD); // contributions.
glPointSize( 3.0 ); // What size are the splats?
glDrawArraysInstancedEXT( GL_POINTS, 0, // Command to actually draw
data->fbo->caustic_PhotonBuffer->GetWidth(),
data->fbo->caustic_PhotonBuffer->GetWidth() );
// Clean up point & blend state, disable shader
glPointSize( 1.0 );
glDisable(GL_BLEND);
data->shader->caustic_SimplePhotonSplat->DisableTexture( GL_TEXTURE0, GL_TEXTURE_2D );
data->shader->caustic_SimplePhotonSplat->DisableShader();
// Stop rendering from a vertex array
glDisableClientState( GL_VERTEX_ARRAY );
glBindBuffer( GL_ARRAY_BUFFER, 0 );
// Disable other miscellaneous GL state & unbind the draw buffer
glEnable( GL_CULL_FACE );
glEnable( GL_DEPTH_TEST );
PopLightMatrices();
cMap->UnbindBuffer();
}
inline void VL_glDrawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
{
if (glDrawArraysInstanced)
glDrawArraysInstanced(mode, first, count, primcount);
else
if (glDrawArraysInstancedARB)
glDrawArraysInstancedARB(mode, first, count, primcount);
else
if (glDrawArraysInstancedEXT)
glDrawArraysInstancedEXT(mode, first, count, primcount);
else
VL_UNSUPPORTED_FUNC();
}
JNIEXPORT void JNICALL Java_org_lwjgl_opengl_EXTDrawInstanced_nglDrawArraysInstancedEXT(JNIEnv *env, jclass clazz, jint mode, jint first, jint count, jint primcount, jlong function_pointer) {
glDrawArraysInstancedEXTPROC glDrawArraysInstancedEXT = (glDrawArraysInstancedEXTPROC)((intptr_t)function_pointer);
glDrawArraysInstancedEXT(mode, first, count, primcount);
}
