mirror of
https://github.com/curioustorvald/Terrarum.git
synced 2026-03-07 20:31:51 +09:00
126 lines
4.2 KiB
GLSL
126 lines
4.2 KiB
GLSL
/*
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Texture binding:
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0 <- Tiles atlas
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1 <- Tiles buffer that holds tiles to be drawn
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2 <- Fluid tiles atlas
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*/
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#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; // vec2(tiles_in_horizontal, tiles_in_vertical)
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uniform ivec2 tilemapDimension;
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uniform sampler2D tilemap; // RGBA8888
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uniform sampler2D tilesAtlas; // terrain, wire, fluids, etc.
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uniform sampler2D tilesBlendAtlas; // weather mix (e.g. yellowed grass)
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uniform float tilesBlend = 0.0; // percentage of blending [0f..1f]. 0: draws tilesAtlas, 1: draws tilesBlendAtlas
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uniform ivec2 tilesInAtlas = ivec2(256, 256);
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uniform ivec2 atlasTexSize = ivec2(4096, 4096);
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ivec2 tileSizeInPx = atlasTexSize / tilesInAtlas;
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uniform vec4 colourFilter = vec4(1, 1, 1, 1); // used by WALL to darken it
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uniform ivec2 cameraTranslation = ivec2(0, 0);
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uniform float drawBreakage = 1f; // set it to 0f to not draw breakage; non-zero value to draw it
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ivec2 getTileXY(int tileNumber) {
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return ivec2(tileNumber % int(tilesInAtlas.x), tileNumber / int(tilesInAtlas.x));
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}
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// return: int=0xaarrggbb
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int _colToInt(vec4 color) {
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return int(color.b * 255) | (int(color.g * 255) << 8) | (int(color.r * 255) << 16) | (int(color.a * 255) << 24);
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}
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// 0x0rggbb where int=0xaarrggbb
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// return: [0..1048575]
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int getTileFromColor(vec4 color) {
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return _colToInt(color) & 0xFFFFF;
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}
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// 0x00r00000 where int=0xaarrggbb
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// return: [0..15]
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int getBreakageFromColor(vec4 color) {
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return (_colToInt(color) >> 20) & 0xF;
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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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// Remember, if there's a compile error, shader SILENTLY won't do anything //
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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; // one used by the tileFromMap
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vec2 flippedFragCoord = vec2(gl_FragCoord.x, screenDimension.y - gl_FragCoord.y) + cameraTranslation; // NO IVEC2!!; this flips Y
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vec2 pxCoord = flippedFragCoord.xy;
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// TODO do I really need mediump for this thing ? (default to smapler2D is lowp)
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vec4 tileFromMap = texture2D(tilemap, flippedFragCoord / overscannedScreenDimension); // <- THE CULPRIT
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int tile = getTileFromColor(tileFromMap);
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int breakage = getBreakageFromColor(tileFromMap);
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ivec2 tileXY = getTileXY(tile);
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ivec2 breakageXY = getTileXY(breakage + 5); // +5 is hard-coded constant that depends on the atlas
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vec2 coordInTile = mod(pxCoord, tileSizeInPx) / tileSizeInPx; // 0..1 regardless of tile position in atlas
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// don't really need highp here; read the GLES spec
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vec2 singleTileSizeInUV = vec2(1) / tilesInAtlas; // constant 0.00390625 for unmodified default uniforms
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vec2 uvCoordForTile = coordInTile * singleTileSizeInUV; // 0..0.00390625 regardless of tile position in atlas
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vec2 uvCoordOffsetTile = tileXY * singleTileSizeInUV; // where the tile starts in the atlas, using uv coord (0..1)
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vec2 uvCoordOffsetBreakage = breakageXY * singleTileSizeInUV;
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vec2 finalUVCoordForTile = uvCoordForTile + uvCoordOffsetTile;// where we should be actually looking for in atlas, using UV coord (0..1)
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vec2 finalUVCoordForBreakage = uvCoordForTile + uvCoordOffsetBreakage;
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// blending a breakage tex with main tex
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vec4 tileCol = texture2D(tilesAtlas, finalUVCoordForTile);
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vec4 tileAltCol = texture2D(tilesBlendAtlas, finalUVCoordForTile);
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vec4 finalTile = mix(tileCol, tileAltCol, tilesBlend);
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vec4 finalBreakage;
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if (drawBreakage == 0f) {
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finalBreakage = vec4(0f);
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}
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else {
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finalBreakage = texture2D(tilesAtlas, finalUVCoordForBreakage);
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}
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vec4 finalColor = vec4(mix(finalTile.rgb, finalBreakage.rgb, finalBreakage.a), finalTile.a);
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gl_FragColor = colourFilter * finalColor;
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}
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