Minor cleanup around additive blending.

NickAger · Mar 8, 2017 · 8c3bdee · 8c3bdee
1 parent 23e2089
commit 8c3bdee
Show file tree

Hide file tree

Showing 4 changed files with 18 additions and 13 deletions.
diff --git a/framework/Source/Mac/PictureOutput.swift b/framework/Source/Mac/PictureOutput.swift
@@ -46,13 +46,11 @@ public class PictureOutput: ImageConsumer {
         clearFramebufferWithColor(Color.transparent)
 
         // Need the blending here to enable non-1.0 alpha on output image
-        glBlendEquation(GLenum(GL_FUNC_ADD))
-        glBlendFunc(GLenum(GL_ONE), GLenum(GL_ONE))
-        glEnable(GLenum(GL_BLEND))
+        enableAdditiveBlending()
 
         renderQuadWithShader(sharedImageProcessingContext.passthroughShader, uniformSettings:ShaderUniformSettings(), vertices:standardImageVertices, inputTextures:[framebuffer.texturePropertiesForOutputRotation(.noRotation)])
 
-        glDisable(GLenum(GL_BLEND))
+        disableBlending()
 
         framebuffer.unlock()
 

diff --git a/framework/Source/OpenGLRendering.swift b/framework/Source/OpenGLRendering.swift
@@ -193,6 +193,16 @@ func attachStencilBuffer(width:GLint, height:GLint) throws -> GLuint {
     return stencilBuffer
 }
 
+public func enableAdditiveBlending() {
+    glBlendEquation(GLenum(GL_FUNC_ADD))
+    glBlendFunc(GLenum(GL_ONE), GLenum(GL_ONE))
+    glEnable(GLenum(GL_BLEND))
+}
+
+public func disableBlending() {
+    glDisable(GLenum(GL_BLEND))
+}
+
 extension String {
     func withNonZeroSuffix(_ suffix:Int) -> String {
         if suffix == 0 {

diff --git a/framework/Source/Operations/Histogram.swift b/framework/Source/Operations/Histogram.swift
@@ -62,10 +62,8 @@ public class Histogram: BasicOperation {
 
         clearFramebufferWithColor(Color.black)
 
-        glBlendEquation(GLenum(GL_FUNC_ADD))
-        glBlendFunc(GLenum(GL_ONE), GLenum(GL_ONE))
-        glEnable(GLenum(GL_BLEND))
-
+        enableAdditiveBlending()
+
         shader.use()
         guard let positionAttribute = shader.attributeIndex("position") else { fatalError("A position attribute was missing from the shader program during rendering.") }
         glVertexAttribPointer(positionAttribute, 4, GLenum(GL_UNSIGNED_BYTE), 0, (GLint(downsamplingFactor) - 1) * 4, data)
@@ -85,7 +83,7 @@ public class Histogram: BasicOperation {
             glDrawArrays(GLenum(GL_POINTS), 0, inputSize.width * inputSize.height / GLint(downsamplingFactor))
         }
 
-        glDisable(GLenum(GL_BLEND))
+        disableBlending()
         data.deallocate(capacity:inputByteSize)
     }
 }
diff --git a/framework/Source/Operations/LineGenerator.swift b/framework/Source/Operations/LineGenerator.swift
@@ -63,13 +63,12 @@ public class LineGenerator: ImageGenerator {
         let lineEndpoints = lines.flatMap{$0.toGLEndpoints()}
         glVertexAttribPointer(positionAttribute, 2, GLenum(GL_FLOAT), 0, 0, lineEndpoints)
 
-        glBlendEquation(GLenum(GL_FUNC_ADD))
-        glBlendFunc(GLenum(GL_ONE), GLenum(GL_ONE))
-        glEnable(GLenum(GL_BLEND))
+
+        enableAdditiveBlending()
 
         glDrawArrays(GLenum(GL_LINES), 0, GLsizei(lines.count) * 2)
 
-        glDisable(GLenum(GL_BLEND))
+        disableBlending()
 
         notifyTargets()
     }