106 lines
3.5 KiB
C++
106 lines
3.5 KiB
C++
// Copyright 2024 Bytedance Inc. All Rights Reserved.
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// Author: tianlei.richard@qq.com (tianlei.richard)
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#include <cmath>
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#include "minus_renderer.h"
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#include "rasterizer.h"
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#include "spdlog/spdlog.h"
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MinusRenderer::MinusRenderer(float near, float far, float fov,
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float aspect_ratio,
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std::vector<Triangle> &&primitives)
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: near_(near), far_(far), fov_(fov), aspect_ratio_(aspect_ratio),
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primitives_(primitives) {
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spdlog::info("fov: {}, aspect ratio: {}", fov_, aspect_ratio_);
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}
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float MinusRenderer::calculate_height(const float fov, const float near) {
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return std::fabs(near) * std::tan(fov * 0.5) * 2;
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}
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float MinusRenderer::calculate_width(const float height, const float ratio) {
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return height * ratio;
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}
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TransformMatrix MinusRenderer::squish_tranform() {
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// Frustum to Cuboid
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return TransformMatrix{{near_, 0, 0, 0},
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{0, near_, 0, 0},
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{0, 0, near_ + far_, -near_ * far_},
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{0, 0, 1, 0}};
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}
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TransformMatrix MinusRenderer::orthographic_tranform() {
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const float height = calculate_height(fov_, near_);
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const float width = calculate_width(height, aspect_ratio_);
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const float right = width * 0.5;
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const float left = -right;
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const float top = height * 0.5;
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const float bottom = -top;
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TransformMatrix m{{1, 0, 0, -0.5 * (right - left)},
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{0, 1, 0, -0.5 * (top - bottom)},
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{0, 0, 1, -0.5 * (far_ - near_)},
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{0, 0, 0, 1}};
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m = TransformMatrix{{2 / (right - left), 0, 0, 0},
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{0, 2 / (top - bottom), 0, 0},
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{0, 0, 2 / std::fabs(far_ - near_), 0},
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{0, 0, 0, 1}} *
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m;
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return m;
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}
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TransformMatrix MinusRenderer::view_port_transform(const float width,
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const float height) {
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return TransformMatrix{{width * 0.5, 0, 0, width * 0.5},
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{0, height * 0.5, 0, height * 0.5},
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{0, 0, 1, 0},
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{0, 0, 0, 1}};
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}
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void MinusRenderer::model_transform(const TransformMatrix &m) {
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for (auto &t : primitives_) {
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t.affine_transform(m);
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}
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}
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void MinusRenderer::view_transform(const TransformMatrix &m) {
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for (auto &t : primitives_) {
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t.affine_transform(m);
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}
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}
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cv::Mat MinusRenderer::render(const int resolution_width,
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const int resolution_height) {
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std::vector<Triangle> primitives = primitives_;
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for (auto &t : primitives) {
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t.projective_transform(squish_tranform());
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t.affine_transform(orthographic_tranform());
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t.affine_transform(
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view_port_transform(resolution_width, resolution_height));
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}
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Rasterizer rasterizer{resolution_width, resolution_height};
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const auto &pixels = rasterizer.rasterize(primitives);
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assert(!pixels.empty());
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cv::Mat color_image(pixels.size(), (pixels[0]).size(), CV_8UC3);
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for (int i = 0; i < pixels.size(); ++i) {
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const auto &row = pixels[i];
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for (int j = 0; j < row.size(); ++j) {
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auto &pixel_color = color_image.at<cv::Vec3b>(pixels.size() - i - 1, j);
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pixel_color =
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cv::Vec3b{static_cast<unsigned char>(
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row[j].x() * std::numeric_limits<char>::max()),
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static_cast<unsigned char>(
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row[j].y() * std::numeric_limits<char>::max()),
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static_cast<unsigned char>(
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row[j].z() * std::numeric_limits<char>::max())};
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}
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}
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return color_image;
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}
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