fix fp16 blur with invalidation

src/render/OpenGL.cpp

@@ -1660,6 +1660,7 @@ SP<IFramebuffer> CHyprOpenGLImpl::blurFramebufferWithDamage(float a, CRegion* or
         static auto PBLEND          = CConfigValue<Config::INTEGER>("render:use_shader_blur_blend");
 
         PMIRRORSWAPFB->bind();
+        GLFB(PMIRRORSWAPFB)->clearAfterInvalidation();
 
         glActiveTexture(GL_TEXTURE0);
 
@@ -1754,6 +1755,7 @@ SP<IFramebuffer> CHyprOpenGLImpl::blurFramebufferWithDamage(float a, CRegion* or
     // draw the things.
     // first draw is swap -> mirr
     PMIRRORFB->bind();
+    GLFB(PMIRRORFB)->clearAfterInvalidation();
     PMIRRORSWAPFB->getTexture()->bind();
 
     // damage region will be scaled, make a temp

src/render/gl/GLFramebuffer.cpp

@@ -171,4 +171,15 @@ void CGLFramebuffer::invalidate(const std::vector<GLenum>& attachments) {
         return;
 
     glInvalidateFramebuffer(GL_FRAMEBUFFER, attachments.size(), attachments.data());
+    m_cleared = false;
+}
+
+void CGLFramebuffer::clearAfterInvalidation() {
+    if (m_cleared)
+        return;
+
+    m_cleared = true;
+    glClearColor(0, 0, 0, 0);
+    g_pHyprOpenGL->scissor(nullptr);
+    glClear(GL_COLOR_BUFFER_BIT);
 }

src/render/gl/GLFramebuffer.hpp

@@ -21,11 +21,15 @@ namespace Render::GL {
         GLuint getFBID();
         void   invalidate(const std::vector<GLenum>& attachments);
 
+        // clear at most once per invalidate()
+        void clearAfterInvalidation();
+
       protected:
         bool internalAlloc(int w, int h, DRMFormat format = DRM_FORMAT_ARGB8888) override;
 
       private:
-        GLuint m_fb = -1;
+        GLuint m_fb      = -1;
+        bool   m_cleared = false;
 
         friend class CGLRenderbuffer;
     };

src/render/shaders/glsl/blur1.glsl

@@ -104,10 +104,10 @@ vec4 blur1(vec2 v_texcoord, sampler2D tex, float radius, vec2 halfpixel, int pas
     // That garbage maps to 0.0-1.0 range with UINT8 buffer and doesn't have any significant impact on the end result.
     // FP16 garbage maps to -65,504 - 65,504 and defines the end result. Clamp it here to 0.0 - 1.0 to get the same quality outcome as with UINT8.
     // Rerendering an undamaged area to get some insignificant color accuracy increase on blur edges isn't worth it.
-    sum += clamp(texture(tex, uv - halfpixel.xy * radius), 0.0, 1.0);
-    sum += clamp(texture(tex, uv + halfpixel.xy * radius), 0.0, 1.0);
-    sum += clamp(texture(tex, uv + vec2(halfpixel.x, -halfpixel.y) * radius), 0.0, 1.0);
-    sum += clamp(texture(tex, uv - vec2(halfpixel.x, -halfpixel.y) * radius), 0.0, 1.0);
+    sum += texture(tex, uv - halfpixel.xy * radius);
+    sum += texture(tex, uv + halfpixel.xy * radius);
+    sum += texture(tex, uv + vec2(halfpixel.x, -halfpixel.y) * radius);
+    sum += texture(tex, uv - vec2(halfpixel.x, -halfpixel.y) * radius);
 
     vec4 color = sum / 8.0;