diff options
Diffstat (limited to 'src/fb/pixfb.cpp')
| -rw-r--r-- | src/fb/pixfb.cpp | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/src/fb/pixfb.cpp b/src/fb/pixfb.cpp new file mode 100644 index 0000000..d4563ca --- /dev/null +++ b/src/fb/pixfb.cpp @@ -0,0 +1,153 @@ +#include "fb/pixfb.h" +#include <array> +#include <cmath> +#include <vector> +#include <cstdint> +#include "math/math_vector.h" +#include "o3d/vertex.h" +#include "o3d/tri_vertex.h" +#include "o3d/vertex_data.h" + +PixelFrameBuffer::PixelFrameBuffer(unsigned int w, unsigned int h) { + resize(w, h); +} + +void PixelFrameBuffer::resize(unsigned int w, unsigned int h) { + this->w = w; + this->h = h; + pixels_vector.resize(w * h); + depth_buf.resize(w * h); + clear(); +} + +unsigned int PixelFrameBuffer::width() const { + return w; +} + +unsigned int PixelFrameBuffer::height() const { + return h; +} + +const uint32_t* PixelFrameBuffer::pixels() const { + return pixels_vector.data(); +} + +void PixelFrameBuffer::clear() { + std::fill(pixels_vector.begin(), pixels_vector.end(), 0x000000FF); + std::fill(depth_buf.begin(), depth_buf.end(), 1.f); + face_ind = -1; +} + +void PixelFrameBuffer::_draw_cropped_triangle(TriangleVertex3 triangle) { + std::array<Vertex3*, 3> sorted_vs = { &triangle.vertex1, &triangle.vertex2, &triangle.vertex3 }; + +#define SWAP_IF_LT(X,Y) ({\ + if (sorted_vs[X]->point.y < sorted_vs[Y]->point.y) {\ + Vertex3* temp = sorted_vs[X];\ + sorted_vs[X] = sorted_vs[Y];\ + sorted_vs[Y] = temp;\ + }\ + }) + SWAP_IF_LT(1, 0); + SWAP_IF_LT(2, 1); + SWAP_IF_LT(1, 0); +#undef SWAP_IF_LT + + Vertex3 middle_vl = *sorted_vs[1]; + float fac = (sorted_vs[1]->point.y - sorted_vs[0]->point.y) / (sorted_vs[2]->point.y - sorted_vs[0]->point.y); + Vertex3 middle_vr{ + { + sorted_vs[0]->point.x + fac * (sorted_vs[2]->point.x - sorted_vs[0]->point.x), + sorted_vs[1]->point.y, + sorted_vs[0]->point.z + fac * (sorted_vs[2]->point.z - sorted_vs[0]->point.z) + }, + VertexData::lerp(sorted_vs[0]->data, sorted_vs[2]->data, fac) + }; + if (middle_vr.point.x < middle_vl.point.x) { + Vertex3 temp = middle_vr; + middle_vr = middle_vl; + middle_vl = temp; + } + + // top triangle + { + if (sorted_vs[0]->point.y != sorted_vs[1]->point.y) { + int top_y = static_cast<int>(std::floor(sorted_vs[0]->point.y + 1.f)); + int bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y - 1.f)); + for (int y = top_y; y <= bottom_y; y++) { + float iy = static_cast<float>(y); + float s = (iy - sorted_vs[0]->point.y) / (sorted_vs[1]->point.y - sorted_vs[0]->point.y); + float xl = sorted_vs[0]->point.x + s * (middle_vl.point.x - sorted_vs[0]->point.x); + float xr = sorted_vs[0]->point.x + s * (middle_vr.point.x - sorted_vs[0]->point.x); + int left_x = static_cast<int>(std::ceil(xl)); + int right_x = static_cast<int>(std::ceil(xr - 1.f)); + for (int x = left_x; x <= right_x; x++) { + float ix = static_cast<float>(x); + float t = (ix - xl) / (xr - xl); + // depth and vd don't take into account perspective + float depth = sorted_vs[0]->point.z + s * (middle_vl.point.z - sorted_vs[0]->point.z + t * (middle_vr.point.z - middle_vl.point.z)); + // VertexData vd = VertexData::bilerp(sorted_vs[0]->data, middle_vl.data, middle_vr.data, s, t); + if (depth < depth_buf[x + y * w]) { + depth_buf[x + y * w] = depth; + pixels_vector[x + y * w] = face_color(); + } + } + } + } + } + + // bottom triangle + { + if (sorted_vs[1]->point.y != sorted_vs[2]->point.y) { + int bottom_y = static_cast<int>(std::floor(sorted_vs[2]->point.y)); + int top_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y)); + for (int y = top_y; y <= bottom_y; y++) { + float iy = static_cast<float>(y); + float s = (iy - sorted_vs[2]->point.y) / (sorted_vs[1]->point.y - sorted_vs[2]->point.y); + float xl = sorted_vs[2]->point.x + s * (middle_vl.point.x - sorted_vs[2]->point.x); + float xr = sorted_vs[2]->point.x + s * (middle_vr.point.x - sorted_vs[2]->point.x); + int left_x = static_cast<int>(std::ceil(xl)); + int right_x = static_cast<int>(std::ceil(xr - 1.f)); + for (int x = left_x; x <= right_x; x++) { + float ix = static_cast<float>(x); + float t = (ix - xl) / (xr - xl); + // depth and vd don't take into account perspective + float depth = sorted_vs[2]->point.z + s * (middle_vl.point.z - sorted_vs[2]->point.z + t * (middle_vr.point.z - middle_vl.point.z)); + // VertexData vd = VertexData::bilerp(sorted_vs[2]->data, middle_vl.data, middle_vr.data, s, t); + if (depth < depth_buf[x + y * w]) { + depth_buf[x + y * w] = depth; + pixels_vector[x + y * w] = face_color(); + } + } + } + } + } +} + +void PixelFrameBuffer::draw_triangle(TriangleVertex4 triangle) { + face_ind++; + for (auto t1 : triangle.crop_z_out(-1.f, 1.f)) { + for (auto t2 : t1.div_by_w().crop_xy_out(-1.f, 1.f, -1.f, 1.f)) { + MathVector2 pp1 = t2.vertex1.point.xy(), + pp2 = t2.vertex2.point.xy(), + pp3 = t2.vertex3.point.xy(); + if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue; + t2.vertex1.point = (t2.vertex1.point + MathVector3{1.f, 1.f, 0.f}) / 2.f; + t2.vertex2.point = (t2.vertex2.point + MathVector3{1.f, 1.f, 0.f}) / 2.f; + t2.vertex3.point = (t2.vertex3.point + MathVector3{1.f, 1.f, 0.f}) / 2.f; + float fw = static_cast<float>(w), fh = static_cast<float>(h); + t2.vertex1.point.x = t2.vertex1.point.x * fw - .5f; + t2.vertex1.point.y = t2.vertex1.point.y * fh - .5f; + t2.vertex2.point.x = t2.vertex2.point.x * fw - .5f; + t2.vertex2.point.y = t2.vertex2.point.y * fh - .5f; + t2.vertex3.point.x = t2.vertex3.point.x * fw - .5f; + t2.vertex3.point.y = t2.vertex3.point.y * fh - .5f; + _draw_cropped_triangle(t2); + } + } +} + +uint32_t PixelFrameBuffer::face_color() const { + int n = face_ind / 2; + return ((n % 2 ? 0xFF000000 : 0x55000000) >> ((n % 6) / 2 * 8)) | 0xFF; +} |