1 files changed, 57 insertions, 0 deletions
diff --git a/tiled.glsl b/tiled.glsl
new file mode 100644
index 0000000..2a0e5d9
--- /dev/null
+++ b/tiled.glsl
@@ -0,0 +1,57 @@
+#version 430
+precision highp float;
+
+in vec3 vertexPos;
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform sampler2D texture1;
+
+uniform vec2 resolution;
+uniform vec2 offset;
+uniform float zoom;
+uniform ivec2 atlasSize;
+uniform int tilemap[4][4];
+
+out vec4 finalColor;
+
+ivec2 calcTileOffset(int tileIndex) {
+    tileIndex -= 1;
+    int x = tileIndex % atlasSize.x;
+    int y = (tileIndex - x) / atlasSize.y;
+    return ivec2(x, y);
+}
+
+vec4 tile(vec2 coords, int tileIndex) {
+    ivec2 texSize = textureSize(texture1, 1);
+
+    // for now just render the first tile
+    
+
+    vec2 tileSize = texSize / atlasSize;
+
+    if (tileIndex == 0
+        || coords.x > tileSize.x
+        || coords.x < 0
+        || coords.y > tileSize.y
+        || coords.y < 0) {
+        return vec4(0.0f, 0.0f, 0.0f, 0.0f);
+    } else {
+        ivec2 tileOffset = calcTileOffset(tileIndex);
+        vec2 texCoords = coords + (tileOffset*tileSize);
+        texCoords /= texSize;
+
+        return texture(texture1, texCoords);
+    }
+}
+
+void main() {
+    vec2 uv = fragTexCoord;
+    uv.x *= resolution.x / resolution.y;
+
+    uv *= zoom;
+    uv -= offset;
+
+    finalColor = tile(uv, tilemap[2][2]);
+}