simplified the tiling shader a bit

assets/tiling.frag

@@ -19,25 +19,22 @@ uniform sampler2D u_texture;
 uniform vec2 screenDimension;
 uniform vec2 tilesInAxes; // basically a screen dimension; vec2(tiles_in_horizontal, tiles_in_vertical)
 
-uniform ivec2 tilemapDimension;
 uniform sampler2D tilemap; // RGBA8888
 
 uniform sampler2D tilesAtlas; // terrain, wire, fluids, etc.
 uniform sampler2D tilesBlendAtlas; // alternative terrain for the weather mix (e.g. yellowed grass)
 uniform float tilesBlend = 0.0; // percentage of blending [0f..1f]. 0: draws tilesAtlas, 1: draws tilesBlendAtlas
 
-uniform ivec2 tilesInAtlas = ivec2(256, 256);
-uniform ivec2 atlasTexSize = ivec2(4096, 4096);
-ivec2 tileSizeInPx = atlasTexSize / tilesInAtlas; // should be like ivec2(16, 16)
+uniform vec2 tilesInAtlas = ivec2(256.0, 256.0);
+uniform vec2 atlasTexSize = ivec2(4096.0, 4096.0);
+vec2 tileSizeInPx = atlasTexSize / tilesInAtlas; // should be like ivec2(16.0, 16.0)
 
 uniform vec4 colourFilter = vec4(1, 1, 1, 1); // used by WALL to darken it
 
-uniform ivec2 cameraTranslation = ivec2(0, 0); // used to offset the drawing
+uniform ivec2 cameraTranslation = ivec2(0, 0); // used to offset the drawing; it's integer because we want the drawing to be pixel-aligned
 
 uniform float drawBreakage = 1.0; // set it to 0f to not draw breakage, 1f to draw it; NEVER set to any other values.
 
-uniform float zoom = 1.0;
-
 
 ivec2 getTileXY(int tileNumber) {
     return ivec2(tileNumber % int(tilesInAtlas.x), tileNumber / int(tilesInAtlas.x));
@@ -70,10 +67,8 @@ void main() {
 
     // default gl_FragCoord takes half-integer (represeting centre of the pixel) -- could be useful for phys solver?
     // This one, however, takes exact integer by rounding down. //
-    vec2 overscannedScreenDimension = tilesInAxes * tileSizeInPx; // how many tiles will fit into a screen; one used by the tileFromMap
+    vec2 overscannedScreenDimension = tilesInAxes * tileSizeInPx; // how many tiles will fit into a screen; one used by the tileFromMap; we need this because screen size is not integer multiple of the tile size
     vec2 flippedFragCoord = vec2(gl_FragCoord.x, screenDimension.y - gl_FragCoord.y) + cameraTranslation; // NO IVEC2!!; this flips Y
-    //vec2 pxCoord = flippedFragCoord.xy; // TODO do I actually need 'pxCoord'?
-    vec2 zoomVec = vec2(zoom);
 
     // get required tile numbers //
 
@@ -83,23 +78,17 @@ void main() {
     ivec2 tileXY = getTileXY(tile);
     ivec2 breakageXY = getTileXY(breakage + 5); // +5 is hard-coded constant that depends on the atlas
 
-    // cauculate the UV coord value for texture sampling //
-
-    //vec2 coordInTile = mod(pxCoord, tileSizeInPx) / tileSizeInPx; // 0..1 regardless of tile position in atlas  // TODO do I actually need 'pxCoord'?
-    vec2 coordInTile = mod(flippedFragCoord, tileSizeInPx) / tileSizeInPx; // 0..1 regardless of tile position in atlas
+    // calculate the UV coord value for texture sampling //
 
     // don't really need highp here; read the GLES spec
-    vec2 singleTileSizeInUV = vec2(1) / tilesInAtlas; // constant 0.00390625 for unmodified default uniforms
-
-    vec2 uvCoordForTile = coordInTile * singleTileSizeInUV; // 0..0.00390625 regardless of tile position in atlas
-
-    vec2 uvCoordOffsetTile = tileXY * singleTileSizeInUV; // where the tile starts in the atlas, using uv coord (0..1)
-    vec2 uvCoordOffsetBreakage = breakageXY * singleTileSizeInUV;
+    vec2 uvCoordForTile = (mod(flippedFragCoord, tileSizeInPx) / tileSizeInPx) / tilesInAtlas; // 0..0.00390625 regardless of tile position in atlas
+    vec2 uvCoordOffsetTile = tileXY / tilesInAtlas; // where the tile starts in the atlas, using uv coord (0..1)
+    vec2 uvCoordOffsetBreakage = breakageXY / tilesInAtlas;
 
     // get final UV coord for the actual sampling //
 
-    vec2 finalUVCoordForTile = (uvCoordForTile + uvCoordOffsetTile);// where we should be actually looking for in atlas, using UV coord (0..1)
-    vec2 finalUVCoordForBreakage = (uvCoordForTile + uvCoordOffsetBreakage);
+    vec2 finalUVCoordForTile = uvCoordForTile + uvCoordOffsetTile;// where we should be actually looking for in atlas, using UV coord (0..1)
+    vec2 finalUVCoordForBreakage = uvCoordForTile + uvCoordOffsetBreakage;
 
     // blending a breakage tex with main tex //