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depth pre-pass when projecting texture

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This commit is contained in:
Nick Fisher
2024-09-19 16:59:01 +08:00
parent 212443cb8e
commit 3b2d7d8c47
1 changed files with 167 additions and 86 deletions
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253
thermion_dart/native/src/UnprojectTexture.cpp
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@@ -20,111 +20,192 @@
#include "CustomGeometry.hpp" #include "CustomGeometry.hpp"
#include "UnprojectTexture.hpp" #include "UnprojectTexture.hpp"
namespace thermion_filament { namespace thermion_filament
{
void UnprojectTexture::unproject(utils::Entity entity, const uint8_t* inputTexture, uint8_t* outputTexture, uint32_t inputWidth, uint32_t inputHeight, bool UnprojectTexture::isInsideTriangle(const math::float2 &p, const math::float2 &a, const math::float2 &b, const math::float2 &c)
uint32_t outputWidth, uint32_t outputHeight) { {
auto& rm = _engine->getRenderableManager(); float d1 = (p.x - b.x) * (a.y - b.y) - (a.x - b.x) * (p.y - b.y);
auto& tm = _engine->getTransformManager(); 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);
}
// Get the inverse view-projection matrix math::float3 UnprojectTexture::barycentric(const math::float2 &p, const math::float2 &a, const math::float2 &b, const math::float2 &c)
math::mat4 invViewProj = Camera::inverseProjection(_camera.getProjectionMatrix()) * _camera.getModelMatrix(); {
math::float2 v0 = b - a;
math::float2 v1 = c - a;
math::float2 v2 = p - a;
// Get the world transform of the entity float d00 = dot(v0, v0);
auto ti = tm.getInstance(entity); float d01 = dot(v0, v1);
math::mat4f worldTransform = tm.getWorldTransform(ti); float d11 = dot(v1, v1);
auto inverseWorldTransform = inverse(worldTransform); float d20 = dot(v2, v0);
float d21 = dot(v2, v1);
// Get vertex, normal, UV, and index data from CustomGeometry float denom = d00 * d11 - d01 * d01;
const float* vertices = _geometry->vertices;
const float* uvs = _geometry->uvs;
const uint16_t* indices = _geometry->indices;
uint32_t numIndices = _geometry->numIndices;
// Iterate over each pixel in the output texture float v = (d11 * d20 - d01 * d21) / denom;
for (uint32_t y = 0; y < outputHeight; ++y) { float w = (d00 * d21 - d01 * d20) / denom;
for (uint32_t x = 0; x < outputWidth; ++x) { float u = 1.0f - v - w;
// Convert output texture coordinates to UV space
math::float2 uv(static_cast<float>(x) / outputWidth, static_cast<float>(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 return math::float3(u, v, w);
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)) { void UnprojectTexture::unproject(utils::Entity entity, const uint8_t *inputTexture, uint8_t *outputTexture,
// Compute barycentric coordinates in UV space uint32_t inputWidth, uint32_t inputHeight,
math::float3 bary = barycentric(uv, uv0, uv1, uv2); uint32_t outputWidth, uint32_t outputHeight)
{
// Interpolate 3D position auto &rm = _engine->getRenderableManager();
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; auto &tm = _engine->getTransformManager();
found = true;
break; 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<float> depthBuffer(inputWidth * inputHeight, std::numeric_limits<float>::infinity());
// Create a buffer to store the triangle index for each pixel
std::vector<int> 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<int>(std::min({screenPos0.x, screenPos1.x, screenPos2.x})));
int maxX = std::min(static_cast<int>(inputWidth) - 1, static_cast<int>(std::max({screenPos0.x, screenPos1.x, screenPos2.x})));
int minY = std::max(0, static_cast<int>(std::min({screenPos0.y, screenPos1.y, screenPos2.y})));
int maxY = std::min(static_cast<int>(inputHeight) - 1, static_cast<int>(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
}
}
} }
} }
}
if (found) { for (uint32_t y = 0; y < outputHeight; ++y)
// Transform the object position to world space {
math::float3 worldPos = (worldTransform * math::float4(objectPos, 1.0f)).xyz; for (uint32_t x = 0; x < outputWidth; ++x)
{
// Project the world position to screen space math::float2 uv(static_cast<float>(x) / outputWidth, static_cast<float>(y) / outputHeight);
math::float4 clipPos = _camera.getProjectionMatrix() * _camera.getViewMatrix() * math::float4(worldPos, 1.0f);
math::float3 ndcPos = clipPos.xyz / clipPos.w;
// Convert NDC to screen coordinates // Use the UV coordinates to get the corresponding 3D position on the renderable
int sx = static_cast<int>((ndcPos.x * 0.5f + 0.5f) * inputWidth); math::float3 objectPos;
int sy = static_cast<int>((1.0f - (ndcPos.y * 0.5f + 0.5f)) * inputHeight); math::float2 interpolatedUV;
bool found = false;
// Ensure we're within the input texture bounds // Iterate over triangles to find which one contains this UV coordinate
if (sx >= 0 && sx < inputWidth && sy >= 0 && sy < inputHeight) { for (size_t i = 0; i < numIndices; i += 3)
// Sample the input texture {
int inputIndex = (sy * inputWidth + sx) * 4; math::float2 uv0 = *(math::float2 *)&uvs[indices[i] * 2];
int outputIndex = (y * outputWidth + x) * 4; math::float2 uv1 = *(math::float2 *)&uvs[indices[i + 1] * 2];
math::float2 uv2 = *(math::float2 *)&uvs[indices[i + 2] * 2];
// Copy the color to the output texture if (isInsideTriangle(uv, uv0, uv1, uv2))
std::copy_n(&inputTexture[inputIndex], 4, &outputTexture[outputIndex]); {
// 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]);
}
}
}
} }
} }
} }
} }
}
math::float3 UnprojectTexture::doUnproject(const math::float2& screenPos, float depth, const math::mat4& invViewProj) { } // namespace thermion_filament
math::float4 clipSpace(screenPos.x * 2.0f - 1.0f, screenPos.y * 2.0f - 1.0f, depth * 2.0f - 1.0f, 1.0f);
math::float4 worldSpace = invViewProj * clipSpace;
return math::float3(worldSpace.xyz) / worldSpace.w;
}
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, v1 = c - a, 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);
}
} // namespace thermion_filament