move blurring to texture object

src/renderer/painter_prerender.cpp

@@ -0,0 +1,25 @@
+#include <llmr/renderer/painter.hpp>
+
+using namespace llmr;
+
+void Painter::renderPrerenderedTexture(Bucket &bucket, const GenericProperties &properties) {
+    const int buffer = 4096 * properties.prerenderBuffer;
+
+    // draw the texture on a quad
+    depthMask(false);
+
+    useProgram(rasterShader->program);
+    rasterShader->setMatrix(matrix);
+    rasterShader->setOpacity(1);
+
+    glDepthRange(strata, 1.0f);
+
+    glActiveTexture(GL_TEXTURE0);
+    rasterShader->setImage(0);
+    rasterShader->setBuffer(buffer);
+    bucket.prerendered->bindTexture();
+    coveringRasterArray.bind(*rasterShader, tileStencilBuffer, BUFFER_OFFSET(0));
+    glDrawArrays(GL_TRIANGLES, 0, (GLsizei)tileStencilBuffer.index());
+
+    depthMask(true);
+}