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https://github.com/Relintai/pandemonium_engine.git
synced 2024-12-23 04:16:50 +01:00
Rework PaintPolygon2D's triangle rasterizer so both color and uv interpolation works properly.
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@ -434,10 +434,9 @@ Ref<Image> PaintPolygon2D::_get_rendered_image() {
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texture_image->lock();
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}
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Vector2 cpoints[3];
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Vector2i cpoints[3];
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Vector2 cuvs[3];
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Color ccolors[3];
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int cinds[3];
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if (colors.size() == 1) {
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for (int j = 0; j < 3; ++j) {
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@ -449,113 +448,172 @@ Ref<Image> PaintPolygon2D::_get_rendered_image() {
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for (int index = 0; index < indices.size(); index += 3) {
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// Rasterize triangle
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// Based on https://www.youtube.com/watch?v=PahbNFypubE
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for (int j = 0; j < 3; ++j) {
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cinds[j] = indices[index + j];
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for (int i = 0; i < 3; ++i) {
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int cind = indices[index + i];
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cpoints[j] = points[cinds[j]];
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cpoints[i] = points[cind].round();
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if (colors.size() > 1) {
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ccolors[j] = colors[cinds[j]];
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ccolors[i] = colors[cind];
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}
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if (use_uvs) {
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cuvs[j] = uvs[cinds[j]];
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cuvs[i] = uvs[cind];
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}
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}
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// Super simple scanline rasterizer
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// Same idea as presented here: https://www.youtube.com/watch?v=PahbNFypubE
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//Sort them
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Vector2i min_coords = Vector2i(INT_MAX, INT_MAX);
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Vector2i max_coords = Vector2i(INT_MIN, INT_MIN);
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for (int j = 0; j < 3; ++j) {
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min_coords.x = MIN(cpoints[j].x, min_coords.x);
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min_coords.y = MIN(cpoints[j].y, min_coords.y);
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max_coords.x = MAX(cpoints[j].x, max_coords.x);
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max_coords.y = MAX(cpoints[j].y, max_coords.y);
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if (cpoints[1].y < cpoints[0].y || (cpoints[1].y == cpoints[0].y && cpoints[1].x < cpoints[0].x)) {
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SWAP(cpoints[0], cpoints[1]);
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SWAP(ccolors[0], ccolors[1]);
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SWAP(cuvs[0], cuvs[1]);
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}
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Vector<Point2i> brenzenham_line_points = Geometry::brenzenham_line(cpoints[0].x, cpoints[1].x, cpoints[0].y, cpoints[1].y);
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brenzenham_line_points.append_array(Geometry::brenzenham_line(cpoints[1].x, cpoints[2].x, cpoints[1].y, cpoints[2].y));
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brenzenham_line_points.append_array(Geometry::brenzenham_line(cpoints[2].x, cpoints[0].x, cpoints[2].y, cpoints[0].y));
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if (cpoints[2].y < cpoints[0].y || (cpoints[2].y == cpoints[0].y && cpoints[2].x < cpoints[0].x)) {
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SWAP(cpoints[0], cpoints[2]);
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SWAP(ccolors[0], ccolors[2]);
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SWAP(cuvs[0], cuvs[2]);
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}
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//Rect2i tri_rect = Rect2i(min_coords, max_coords - min_coords);
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if (cpoints[2].y < cpoints[1].y || (cpoints[2].y == cpoints[1].y && cpoints[2].x < cpoints[1].x)) {
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SWAP(cpoints[1], cpoints[2]);
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SWAP(ccolors[1], ccolors[2]);
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SWAP(cuvs[1], cuvs[2]);
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}
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const int blp_size = brenzenham_line_points.size();
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const Point2i *blp_ptr = brenzenham_line_points.ptr();
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if (cpoints[0].y == cpoints[2].y) {
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continue;
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}
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int fys = MAX(0, min_coords.y);
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int fye = MIN(_size.y, max_coords.y);
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bool shortside = (cpoints[1].y - cpoints[0].y) * (cpoints[2].x - cpoints[0].x) < (cpoints[1].x - cpoints[0].x) * (cpoints[2].y - cpoints[0].y);
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for (int y = fys; y < fye; ++y) {
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// Current scanline:
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// . . . . psx X X X X X pse . . . .
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Slope sides[2];
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int psx = INT_MAX;
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int pex = INT_MIN;
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sides[!shortside].setup_position(cpoints[0], cpoints[2], cpoints[2].y - cpoints[0].y);
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sides[!shortside].setup_color(ccolors[0], ccolors[2], cpoints[2].y - cpoints[0].y);
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for (int i = 0; i < blp_size; ++i) {
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Point2i p = blp_ptr[i];
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if (use_uvs) {
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sides[!shortside].setup_uv(cuvs[0], cuvs[2], cpoints[2].y - cpoints[0].y);
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}
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if (p.y != y) {
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continue;
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}
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if (p.x < psx) {
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psx = p.x;
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}
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if (p.x > pex) {
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pex = p.x;
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}
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}
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if (psx == INT_MIN || pex == INT_MAX) {
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continue;
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}
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// maybe?
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// pse -= 1;
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float interpy = (y - min_coords.y) / (float)(max_coords.y - min_coords.y);
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Vector2 uvsy;
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Vector2 uvey;
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if (cpoints[0].y < cpoints[1].y) {
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sides[shortside].setup_position(cpoints[0], cpoints[1], cpoints[1].y - cpoints[0].y);
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sides[shortside].setup_color(ccolors[0], ccolors[1], cpoints[1].y - cpoints[0].y);
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if (use_uvs) {
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uvsy = cuvs[0].linear_interpolate(cuvs[1], interpy);
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uvey = cuvs[0].linear_interpolate(cuvs[2], interpy);
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sides[shortside].setup_uv(cuvs[0], cuvs[1], cpoints[1].y - cpoints[0].y);
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}
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Color colorsy = ccolors[0].linear_interpolate(ccolors[1], interpy);
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Color colorey = ccolors[0].linear_interpolate(ccolors[2], interpy);
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int starty = MAX(0, cpoints[0].y);
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int endy = MIN(cpoints[1].y, _size.y);
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int fxs = MAX(0, psx);
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int fxe = MIN(_size.x, pex);
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for (int y = starty; y < endy; ++y) {
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Slope s;
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s.setup_color(sides[0].color_current, sides[1].color_current, sides[1].position_current.x - sides[0].position_current.x);
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if (use_uvs) {
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s.setup_uv(sides[0].uv_current, sides[1].uv_current, sides[1].position_current.x - sides[0].position_current.x);
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}
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for (int x = fxs; x < fxe; ++x) {
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//Vector2 point = Vector2(x, y);
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int startx = MAX(0, sides[0].position_current.x);
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int endx = MIN(sides[1].position_current.x, _size.x);
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float interpx = (x - psx) / (float)(pex - psx);
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for (int x = startx; x < endx; ++x) {
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Color color = s.color_current;
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Color color = colorsy.linear_interpolate(colorey, interpx);
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if (use_uvs) {
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Vector2 uv = s.uv_current;
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uv.x = CLAMP(uv.x, 0, 1);
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uv.y = CLAMP(uv.y, 0, 1);
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Vector2 imgcoord = uv * texture_image_size;
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imgcoord.x = CLAMP(imgcoord.x, 0, texture_image_size.x - 1);
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imgcoord.y = CLAMP(imgcoord.y, 0, texture_image_size.y - 1);
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Color img_color = texture_image->get_pixelv(imgcoord);
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color *= img_color;
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}
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_rendered_image->set_pixelv(Vector2(x, y), color);
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s.advance_color();
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if (use_uvs) {
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s.advance_uv();
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}
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}
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sides[0].advance();
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sides[1].advance();
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if (use_uvs) {
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Vector2 uv = uvsy.linear_interpolate(uvey, interpx);
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sides[0].advance_uv();
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sides[1].advance_uv();
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}
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}
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}
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Vector2 imgcoord = uv * texture_image_size;
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if (cpoints[1].y < cpoints[2].y) {
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sides[shortside].setup_position(cpoints[1], cpoints[2], cpoints[2].y - cpoints[1].y);
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sides[shortside].setup_color(ccolors[1], ccolors[2], cpoints[2].y - cpoints[1].y);
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imgcoord.x = CLAMP(imgcoord.x, 0, texture_image_size.x - 1);
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imgcoord.y = CLAMP(imgcoord.y, 0, texture_image_size.y - 1);
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if (use_uvs) {
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sides[shortside].setup_uv(cuvs[1], cuvs[2], cpoints[2].y - cpoints[1].y);
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}
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Color img_color = texture_image->get_pixelv(imgcoord);
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int starty = MAX(0, cpoints[1].y);
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int endy = MIN(cpoints[2].y, _size.y);
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color *= img_color;
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for (int y = starty; y < endy; ++y) {
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Slope s;
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s.setup_color(sides[0].color_current, sides[1].color_current, sides[1].position_current.x - sides[0].position_current.x);
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if (use_uvs) {
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s.setup_uv(sides[0].uv_current, sides[1].uv_current, sides[1].position_current.x - sides[0].position_current.x);
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}
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_rendered_image->set_pixelv(Vector2(x, y), color);
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int startx = MAX(0, sides[0].position_current.x);
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int endx = MIN(sides[1].position_current.x, _size.x);
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for (int x = startx; x < endx; ++x) {
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Color color = s.color_current;
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if (use_uvs) {
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Vector2 uv = s.uv_current;
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uv.x = CLAMP(uv.x, 0, 1);
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uv.y = CLAMP(uv.y, 0, 1);
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Vector2 imgcoord = uv * texture_image_size;
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imgcoord.x = CLAMP(imgcoord.x, 0, texture_image_size.x - 1);
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imgcoord.y = CLAMP(imgcoord.y, 0, texture_image_size.y - 1);
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Color img_color = texture_image->get_pixelv(imgcoord);
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color *= img_color;
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}
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_rendered_image->set_pixelv(Vector2(x, y), color);
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s.advance_color();
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if (use_uvs) {
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s.advance_uv();
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}
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}
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sides[0].advance();
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sides[1].advance();
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if (use_uvs) {
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sides[0].advance_uv();
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sides[1].advance_uv();
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}
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}
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}
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}
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@ -126,6 +126,49 @@ public:
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PaintPolygon2D();
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virtual ~PaintPolygon2D();
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protected:
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struct Slope {
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Vector2 position_current;
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Vector2 position_step;
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Vector2 uv_current;
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Vector2 uv_step;
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Color color_current;
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Color color_step;
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_FORCE_INLINE_ void setup_position(Vector2 begin, Vector2 end, float num_steps) {
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float inv_step = 1.0 / num_steps;
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position_step = (end - begin) * Vector2(inv_step, inv_step);
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position_current = begin;
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}
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_FORCE_INLINE_ void setup_color(Color begin, Color end, float num_steps) {
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float inv_step = 1.0 / num_steps;
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color_step = (end - begin) * Color(inv_step, inv_step, inv_step);
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color_current = begin;
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}
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_FORCE_INLINE_ void setup_uv(Vector2 begin, Vector2 end, float num_steps) {
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float inv_step = 1.0 / num_steps;
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uv_step = (end - begin) * Vector2(inv_step, inv_step);
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uv_current = begin;
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}
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_FORCE_INLINE_ void advance() {
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position_current += position_step;
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color_current += color_step;
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}
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_FORCE_INLINE_ void advance_color() {
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color_current += color_step;
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}
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_FORCE_INLINE_ void advance_uv() {
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uv_current += uv_step;
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}
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};
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};
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#endif // POLYGON_2D_H
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