#include #include #include #include #include #include #include #include #include #include #include #include #include #include "Log.hpp" #include #include #include #include "CustomGeometry.hpp" #include "UnprojectTexture.hpp" namespace thermion_filament { bool UnprojectTexture::isInsideTriangle(const math::float2 &p, const math::float2 &a, const math::float2 &b, const math::float2 &c) { float d1 = (p.x - b.x) * (a.y - b.y) - (a.x - b.x) * (p.y - b.y); float d2 = (p.x - c.x) * (b.y - c.y) - (b.x - c.x) * (p.y - c.y); float d3 = (p.x - a.x) * (c.y - a.y) - (c.x - a.x) * (p.y - a.y); return (d1 >= 0 && d2 >= 0 && d3 >= 0) || (d1 <= 0 && d2 <= 0 && d3 <= 0); } math::float3 UnprojectTexture::barycentric(const math::float2 &p, const math::float2 &a, const math::float2 &b, const math::float2 &c) { math::float2 v0 = b - a; math::float2 v1 = c - a; math::float2 v2 = p - a; float d00 = dot(v0, v0); float d01 = dot(v0, v1); float d11 = dot(v1, v1); float d20 = dot(v2, v0); float d21 = dot(v2, v1); float denom = d00 * d11 - d01 * d01; float v = (d11 * d20 - d01 * d21) / denom; float w = (d00 * d21 - d01 * d20) / denom; float u = 1.0f - v - w; return math::float3(u, v, w); } void UnprojectTexture::unproject(utils::Entity entity, const uint8_t *inputTexture, uint8_t *outputTexture, uint32_t inputWidth, uint32_t inputHeight, uint32_t outputWidth, uint32_t outputHeight) { auto &rm = _engine->getRenderableManager(); auto &tm = _engine->getTransformManager(); math::mat4 invViewProj = Camera::inverseProjection(_camera.getProjectionMatrix()) * _camera.getModelMatrix(); auto ti = tm.getInstance(entity); math::mat4f worldTransform = tm.getWorldTransform(ti); auto inverseWorldTransform = inverse(worldTransform); const float *vertices = _geometry->vertices; const float *uvs = _geometry->uvs; const uint16_t *indices = _geometry->indices; uint32_t numIndices = _geometry->numIndices; // Create a depth buffer std::vector depthBuffer(inputWidth * inputHeight, std::numeric_limits::infinity()); // Create a buffer to store the triangle index for each pixel std::vector triangleIndexBuffer(inputWidth * inputHeight, -1); auto max = 0.0f; auto min = 99.0f; // Depth pre-pass for (size_t i = 0; i < numIndices; i += 3) { math::float3 v0(vertices[indices[i] * 3], vertices[indices[i] * 3 + 1], vertices[indices[i] * 3 + 2]); math::float3 v1(vertices[indices[i + 1] * 3], vertices[indices[i + 1] * 3 + 1], vertices[indices[i + 1] * 3 + 2]); math::float3 v2(vertices[indices[i + 2] * 3], vertices[indices[i + 2] * 3 + 1], vertices[indices[i + 2] * 3 + 2]); math::float2 uv0(uvs[(indices[i] * 2)], uvs[(indices[i] * 2) + 1]); math::float2 uv1(uvs[(indices[i + 1] * 2)], uvs[(indices[i + 1] * 2) + 1]); math::float2 uv2(uvs[(indices[i + 2] * 2)], uvs[(indices[i + 2] * 2) + 1]); // Transform vertices to world space v0 = (worldTransform * math::float4(v0, 1.0f)).xyz; v1 = (worldTransform * math::float4(v1, 1.0f)).xyz; v2 = (worldTransform * math::float4(v2, 1.0f)).xyz; // Project vertices to screen space math::float4 clipPos0 = _camera.getProjectionMatrix() * _camera.getViewMatrix() * math::float4(v0, 1.0f); math::float4 clipPos1 = _camera.getProjectionMatrix() * _camera.getViewMatrix() * math::float4(v1, 1.0f); math::float4 clipPos2 = _camera.getProjectionMatrix() * _camera.getViewMatrix() * math::float4(v2, 1.0f); math::float3 ndcPos0 = clipPos0.xyz / clipPos0.w; math::float3 ndcPos1 = clipPos1.xyz / clipPos1.w; math::float3 ndcPos2 = clipPos2.xyz / clipPos2.w; // Convert NDC to screen coordinates math::float2 screenPos0((ndcPos0.x * 0.5f + 0.5f) * inputWidth, (1.0f - (ndcPos0.y * 0.5f + 0.5f)) * inputHeight); math::float2 screenPos1((ndcPos1.x * 0.5f + 0.5f) * inputWidth, (1.0f - (ndcPos1.y * 0.5f + 0.5f)) * inputHeight); math::float2 screenPos2((ndcPos2.x * 0.5f + 0.5f) * inputWidth, (1.0f - (ndcPos2.y * 0.5f + 0.5f)) * inputHeight); // Compute bounding box of the triangle int minX = std::max(0, static_cast(std::min({screenPos0.x, screenPos1.x, screenPos2.x}))); int maxX = std::min(static_cast(inputWidth) - 1, static_cast(std::max({screenPos0.x, screenPos1.x, screenPos2.x}))); int minY = std::max(0, static_cast(std::min({screenPos0.y, screenPos1.y, screenPos2.y}))); int maxY = std::min(static_cast(inputHeight) - 1, static_cast(std::max({screenPos0.y, screenPos1.y, screenPos2.y}))); // Iterate over the bounding box for (int y = minY; y <= maxY; ++y) { for (int x = minX; x <= maxX; ++x) { math::float2 pixelPos(x + 0.5f, y + 0.5f); if (isInsideTriangle(pixelPos, screenPos0, screenPos1, screenPos2)) { math::float3 bary = barycentric(pixelPos, screenPos0, screenPos1, screenPos2); // Interpolate depth float depth = bary.x * ndcPos0.z + bary.y * ndcPos1.z + bary.z * ndcPos2.z; // Depth test if (depth < depthBuffer[y * inputWidth + x]) { if (depth > max) { max = depth; } if (depth < min) { min = depth; } depthBuffer[y * inputWidth + x] = depth; triangleIndexBuffer[y * inputWidth + x] = i / 3; // Store triangle index } } } } } for (uint32_t y = 0; y < outputHeight; ++y) { for (uint32_t x = 0; x < outputWidth; ++x) { math::float2 uv(static_cast(x) / outputWidth, static_cast(y) / outputHeight); // Use the UV coordinates to get the corresponding 3D position on the renderable math::float3 objectPos; math::float2 interpolatedUV; bool found = false; // Iterate over triangles to find which one contains this UV coordinate for (size_t i = 0; i < numIndices; i += 3) { math::float2 uv0 = *(math::float2 *)&uvs[indices[i] * 2]; math::float2 uv1 = *(math::float2 *)&uvs[indices[i + 1] * 2]; math::float2 uv2 = *(math::float2 *)&uvs[indices[i + 2] * 2]; if (isInsideTriangle(uv, uv0, uv1, uv2)) { // Compute barycentric coordinates in UV space math::float3 bary = barycentric(uv, uv0, uv1, uv2); // Interpolate 3D position math::float3 v0(vertices[indices[i] * 3], vertices[indices[i] * 3 + 1], vertices[indices[i] * 3 + 2]); math::float3 v1(vertices[indices[i + 1] * 3], vertices[indices[i + 1] * 3 + 1], vertices[indices[i + 1] * 3 + 2]); math::float3 v2(vertices[indices[i + 2] * 3], vertices[indices[i + 2] * 3 + 1], vertices[indices[i + 2] * 3 + 2]); objectPos = v0 * bary.x + v1 * bary.y + v2 * bary.z; interpolatedUV = uv; // Find the screen coordinates on the input texture math::float3 worldPos = (worldTransform * math::float4(objectPos, 1.0f)).xyz; // Project the world position to screen space math::float4 clipPos = _camera.getProjectionMatrix() * _camera.getViewMatrix() * math::float4(worldPos, 1.0f); math::float3 ndcPos = clipPos.xyz / clipPos.w; // Convert NDC to screen coordinates uint32_t screenX = (ndcPos.x * 0.5f + 0.5f) * inputWidth; uint32_t screenY = (1.0f - (ndcPos.y * 0.5f + 0.5f)) * inputHeight; if (triangleIndexBuffer[(screenY * inputWidth) + screenX] == i / 3) { if (screenX >= 0 && screenX < inputWidth && screenY >= 0 && screenY < inputHeight) { int inputIndex = (screenY * inputWidth + screenX) * 4; int outputIndex = (y * outputWidth + x) * 4; std::copy_n(&inputTexture[inputIndex], 4, &outputTexture[outputIndex]); } } } } } } } } // namespace thermion_filament