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#include "shadowStenciller.h"
#include "gfx/gl/program.h"
#include "gfx/gl/shaders/fs-shadowStencil.h"
#include "gfx/gl/shaders/gs-shadowStencil.h"
#include "gfx/gl/shaders/vs-shadowStencil.h"
#include "gfx/lightDirection.h"
#include "gfx/models/mesh.h"
#include "glArrays.h"
#include "gl_traits.h"
#include "maths.h"
#include <stdexcept>
ShadowStenciller::ShadowStenciller() :
shadowCaster {shadowStencil_vs, shadowStencil_gs, shadowStencil_fs}, viewProjections {}
{
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
void
ShadowStenciller::setLightDirection(const LightDirection & lightDir)
{
viewProjections = [&lightDir]<GLint... Ep>(std::integer_sequence<GLint, Ep...>) {
constexpr float STEP = two_pi / STENCIL_ANGLES<decltype(two_pi)>;
return std::array {rotate_pitch<4>(half_pi - lightDir.position().y)
* rotate_yaw<4>((Ep * STEP) - lightDir.position().x)...};
}(std::make_integer_sequence<GLint, STENCIL_ANGLES<GLint>>());
}
glTexture
ShadowStenciller::createStencilTexture(GLsizei width, GLsizei height)
{
glTexture stencil;
glBindTexture(GL_TEXTURE_2D_ARRAY, stencil);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexParameter(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameter(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameter(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameter(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_DEPTH_COMPONENT, width, height, STENCIL_ANGLES<GLint>, 0,
GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, nullptr);
return stencil;
}
void
ShadowStenciller::renderStencil(const glTexture & stencil, const MeshBase & mesh, const Texture::AnyPtr texture) const
{
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, stencil, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
throw std::runtime_error("Stencil framebuffer not complete!");
}
if (texture) {
texture->bind();
}
glUseProgram(shadowCaster);
glClear(GL_DEPTH_BUFFER_BIT);
const auto stencilSize = Texture::getSize(stencil);
glViewport(0, 0, stencilSize.x, stencilSize.y);
const auto & centre = mesh.getDimensions().centre;
const auto & size = mesh.getDimensions().size;
glUniform(viewProjectionLoc,
std::span<const glm::mat4> {viewProjections *
[extentsMat = glm::translate(glm::ortho(-size, size, -size, size, -size, size), -centre)](
const auto & viewProjection) {
return viewProjection * extentsMat;
}});
mesh.Draw();
}
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