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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/models/mesh.h"
#include "glArrays.h"
#include "gl_traits.h"
#include "maths.h"
#include <stdexcept>
namespace {
static constexpr std::array<float, 8> anglesEigthPi {-3, -2, -1, 0, 1, 2, 3, 4};
static const auto angles = anglesEigthPi * [](auto ep) {
return rotate_yaw(ep * quarter_pi);
};
}
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 Direction3D & lightDir, const Direction3D & lightDirUp)
{
lightDirMat = glm::lookAt(-lightDir, {}, lightDirUp);
viewProjections = angles * [this](const auto & a) {
return lightDirMat * a;
};
}
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, 8, 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);
glViewport(0, 0, 256, 256);
const auto & centre = mesh.getDimensions().centre;
const auto & size = mesh.getDimensions().size;
const auto extentsMat
= glm::translate(glm::ortho(-size, size, -size, size, -size, size), {-centre.x, -centre.z, -centre.y});
glUniform(viewProjectionLoc, std::span<const glm::mat4> {viewProjections * [&](const auto & vp) {
return extentsMat * vp;
}});
mesh.Draw();
}
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