mirror of
https://github.com/curioustorvald/Terrarum.git
synced 2026-03-07 20:31:51 +09:00
88 lines
2.9 KiB
GLSL
88 lines
2.9 KiB
GLSL
#version 120
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#ifdef GL_ES
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precision mediump float;
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#endif
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#extension GL_EXT_gpu_shader4 : enable
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//layout(origin_upper_left) in vec4 gl_FragCoord; // commented; requires #version 150 or later
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// gl_FragCoord is origin to bottom-left
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varying vec4 v_color;
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varying vec2 v_texCoords;
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uniform sampler2D u_texture;
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uniform vec2 screenDimension;
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uniform vec2 tilesInAxes;
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uniform ivec2 tilemapDimension;
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uniform sampler2D tilemap; // MUST be RGBA8888
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uniform sampler2D tilesAtlas;
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uniform sampler2D backgroundTexture;
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uniform ivec2 tileInAtlas = ivec2(256, 256);
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uniform ivec2 atlasTexSize = ivec2(4096, 4096);
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//uniform vec2 tileInDim; // vec2(tiles_in_horizontal, tiles_in_vertical)
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uniform vec2 cameraTranslation = vec2(0, 0); // Y-flipped
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uniform int tileSizeInPx = 16;
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ivec2 getTileXY(int tileNumber) {
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return ivec2(tileNumber % int(tileInAtlas.x), tileNumber / int(tileInAtlas.x));
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}
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int getTileFromColor(vec4 color) {
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return int(color.b * 255) + (int(color.g * 255) * 256) + (int(color.r * 255) * 65536);
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}
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void main() {
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// READ THE FUCKING MANUAL, YOU DONKEY !! //
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// This code purposedly uses flipped fragcoord. //
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// Make sure you don't use gl_FragCoord unknowingly! //
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// default gl_FragCoord takes half-integer (represeting centre of the pixel) -- could be useful for phys solver?
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// This one, however, takes exact integer by rounding down. //
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vec2 overscannedScreenDimension = tilesInAxes * tileSizeInPx;
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vec2 flippedFragCoord = vec2(v_texCoords.x * screenDimension.x, (1 - v_texCoords.y) * screenDimension.y); // NO IVEC2!!
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vec2 pxCoord = flippedFragCoord.xy + cameraTranslation;
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mediump vec4 tileFromMap = texture2D(tilemap, flippedFragCoord / overscannedScreenDimension); // <- THE CULPRIT
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int tile = getTileFromColor(tileFromMap);
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ivec2 tileXY = getTileXY(tile);
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vec2 coordInTile = mod(pxCoord, tileSizeInPx) / tileSizeInPx; // 0..1 regardless of tile position in atlas
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highp vec2 singleTileSizeInUV = vec2(1) / tileInAtlas; // 0.00390625
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highp vec2 uvCoordForTile = coordInTile * singleTileSizeInUV; // 0..0.00390625 regardless of tile position in atlas
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highp vec2 uvCoordOffset = tileXY * singleTileSizeInUV; // where the tile starts in the atlas, using uv coord (0..1)
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highp vec2 finalUVCoordForTile = uvCoordForTile + uvCoordOffset;// where we should be actually looking for in atlas, using UV coord (0..1)
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gl_FragColor = texture2D(tilesAtlas, finalUVCoordForTile);
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//gl_FragColor = texture2D(tilemap, v_texCoords); // tilemap seems normal...
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//gl_FragColor = tileFromMap; // <- oh, THIS WAS THE CULPRIT!
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//gl_FragColor = fragInAtlas;
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//gl_FragColor = vec4((gl_FragCoord.xy / vec2(512, 512)), 0, 1.0);
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//vec4 atlascol = texture2D(tilesAtlas, v_texCoords);
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//vec4 tilemapcol = texture2D(tilemap, v_texCoords);
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//gl_FragColor = atlascol * tilemapcol;
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//gl_FragColor = vec4(v_texCoords.x, v_texCoords.y, 0, 1.0);
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}
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