84 lines
2.8 KiB
C++
84 lines
2.8 KiB
C++
//
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// Created by Wouter Groeneveld on 11/07/20.
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//
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#include <libgba-bitmap-engine/renderer/renderer.h>
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#include <libgba-bitmap-engine/renderer/gba_engine.h>
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#include <libgba-bitmap-engine/math.h>
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#include <libgba-bitmap-engine/background/text_stream.h>
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// drawing line between 2 points from left to right
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// papb -> pcpd
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// pa, pb, pc, pd must then be sorted before
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void RasterizerRenderer::processScanLine(FIXED y, const VectorFx& pa, const VectorFx& pb, const VectorFx& pc, const VectorFx& pd, COLOR color) {
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FIXED gradient1 = VectorFx::gradient(y, pa, pb), gradient2 = VectorFx::gradient(y, pc, pd);
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int sx = fx2int(interpolate(pa.x(), pb.x(), gradient1));
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int ex = fx2int(interpolate(pc.x(), pd.x(), gradient2));
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int yy = fx2int(y);
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engine.get()->plotLine(sx, yy, ex, yy, color);
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}
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void RasterizerRenderer::plotTriangle(const VectorFx& pt1, const VectorFx& pt2, const VectorFx& pt3, COLOR color) {
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// Sorting the points in order to always have this order on screen p1, p2 & p3
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// with p1 always up (thus having the Y the lowest possible to be near the top screen)
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// then p2 between p1 & p3
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auto p1 = &pt1, p2 = &pt2, p3 = &pt3;
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if (p1->y() > p2->y()) {
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auto temp = p2;
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p2 = p1;
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p1 = temp;
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}
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if (p2->y() > p3->y()) {
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auto temp = p2;
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p2 = p3;
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p3 = temp;
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}
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if (p1->y() > p2->y()) {
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auto temp = p2;
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p2 = p1;
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p1 = temp;
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}
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FIXED dP1P2 = VectorFx::slope(*p1, *p2), dP1P3 = VectorFx::slope(*p1, *p3);
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if (dP1P2 > dP1P3) {
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for (auto y = p1->y(); y <= p3->y(); y+=ONE) {
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if (y < p2->y()) {
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processScanLine(y, *p1, *p3, *p1, *p2, color);
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} else {
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processScanLine(y, *p1, *p3, *p2, *p3, color);
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}
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}
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} else {
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for (auto y = p1->y(); y <= p3->y(); y+=ONE) {
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if (y < p2->y()) {
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processScanLine(y, *p1, *p2, *p1, *p3, color);
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} else {
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processScanLine(y, *p2, *p3, *p1, *p3, color);
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}
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}
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}
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}
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void RasterizerRenderer::render(const MatrixFx &transformationMatrix, const Mesh *mesh) {
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bool colorSwitch = false;
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int i = 0;
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for (auto &face : mesh->faces()) {
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auto &vertexA = mesh->vertices()[face.a];
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auto &vertexB = mesh->vertices()[face.b];
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auto &vertexC = mesh->vertices()[face.c];
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auto pixelA = engine->project(*vertexA.get(), transformationMatrix);
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auto pixelB = engine->project(*vertexB.get(), transformationMatrix);
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auto pixelC = engine->project(*vertexC.get(), transformationMatrix);
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COLOR cI = ONE + fxmul(fxdiv(int2fx(i), int2fx(mesh->faces().size())), int2fx(250));
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plotTriangle(pixelA, pixelB, pixelC, fx2int(cI));
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colorSwitch = !colorSwitch;
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i++;
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}
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} |