| uniform highp vec2 pixelSize; |
| uniform highp mat4 matrix; |
| uniform lowp float opacity; |
| |
| attribute highp vec4 vertex; |
| attribute lowp vec4 vertexColor; |
| attribute highp vec2 vertexOffset; |
| |
| varying lowp vec4 color; |
| |
| void main() |
| { |
| highp vec4 pos = matrix * vertex; |
| gl_Position = pos; |
| |
| if (vertexOffset.x != 0.) { |
| highp vec4 delta = matrix[0] * vertexOffset.x; |
| highp vec2 dir = delta.xy * pos.w - pos.xy * delta.w; |
| highp vec2 ndir = .5 * pixelSize * normalize(dir / pixelSize); |
| dir -= ndir * delta.w * pos.w; |
| highp float numerator = dot(dir, ndir * pos.w * pos.w); |
| highp float scale = 0.0; |
| if (numerator < 0.0) |
| scale = 1.0; |
| else |
| scale = min(1.0, numerator / dot(dir, dir)); |
| gl_Position += scale * delta; |
| } |
| |
| if (vertexOffset.y != 0.) { |
| highp vec4 delta = matrix[1] * vertexOffset.y; |
| highp vec2 dir = delta.xy * pos.w - pos.xy * delta.w; |
| highp vec2 ndir = .5 * pixelSize * normalize(dir / pixelSize); |
| dir -= ndir * delta.w * pos.w; |
| highp float numerator = dot(dir, ndir * pos.w * pos.w); |
| highp float scale = 0.0; |
| if (numerator < 0.0) |
| scale = 1.0; |
| else |
| scale = min(1.0, numerator / dot(dir, dir)); |
| gl_Position += scale * delta; |
| } |
| |
| color = vertexColor * opacity; |
| } |