diff options
Diffstat (limited to 'src/mbgl/shaders/raster.cpp')
-rw-r--r-- | src/mbgl/shaders/raster.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/mbgl/shaders/raster.cpp b/src/mbgl/shaders/raster.cpp index eb7a2db240..98291bfec6 100644 --- a/src/mbgl/shaders/raster.cpp +++ b/src/mbgl/shaders/raster.cpp @@ -20,7 +20,12 @@ varying vec2 v_pos1; void main() { gl_Position = u_matrix * vec4(a_pos, 0, 1); - v_pos0 = (((a_texture_pos / 32767.0) - 0.5) / u_buffer_scale ) + 0.5; + // We are using Int16 for texture position coordinates to give us enough precision for + // fractional coordinates. We use 8192 to scale the texture coordinates in the buffer + // as an arbitrarily high number to preserve adequate precision when rendering. + // This is also the same value as the EXTENT we are using for our tile buffer pos coordinates, + // so math for modifying either is consistent. + v_pos0 = (((a_texture_pos / 8192.0) - 0.5) / u_buffer_scale ) + 0.5; v_pos1 = (v_pos0 * u_scale_parent) + u_tl_parent; } @@ -45,6 +50,12 @@ void main() { // read and cross-fade colors from the main and parent tiles vec4 color0 = texture2D(u_image0, v_pos0); vec4 color1 = texture2D(u_image1, v_pos1); + if (color0.a > 0.0) { + color0.rgb = color0.rgb / color0.a; + } + if (color1.a > 0.0) { + color1.rgb = color1.rgb / color1.a; + } vec4 color = mix(color0, color1, u_fade_t); color.a *= u_opacity; vec3 rgb = color.rgb; |