all: remove unused conditions

Now Kage shaders are always used.

The situtation is different from when we fixed for #1355, so we removed
the fast path for #1335. We have to re-check the current performance.

Updates #1355

internal/atlas/image.go

@@ -455,12 +455,7 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 	}
 
 	var offsets [graphics.ShaderImageCount - 1][2]float32
-	var s *restorable.Shader
 	var imgs [graphics.ShaderImageCount]*restorable.Image
-	if shader == nil {
-		// Fast path for rendering without a shader (#1355).
-		imgs[0] = srcs[0].backend.restorable
-	} else {
 	for i, subimageOffset := range subimageOffsets {
 		src := srcs[i+1]
 		if src == nil {
@@ -470,16 +465,14 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 		offsets[i][0] = float32(ox+src.paddingSize()) - oxf + subimageOffset[0]
 		offsets[i][1] = float32(oy+src.paddingSize()) - oyf + subimageOffset[1]
 	}
-		s = shader.shader
 	for i, src := range srcs {
 		if src == nil {
 			continue
 		}
 		imgs[i] = src.backend.restorable
 	}
-	}
 
-	i.backend.restorable.DrawTriangles(imgs, offsets, vertices, indices, mode, dstRegion, srcRegion, s, uniforms, evenOdd)
+	i.backend.restorable.DrawTriangles(imgs, offsets, vertices, indices, mode, dstRegion, srcRegion, shader.shader, uniforms, evenOdd)
 
 	for _, src := range srcs {
 		if src == nil {

internal/buffered/image.go

@@ -156,24 +156,16 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, vertices [
 		}
 	}
 
-	var s *atlas.Shader
 	var imgs [graphics.ShaderImageCount]*atlas.Image
-	if shader == nil {
-		// Fast path for rendering without a shader (#1355).
-		img := srcs[0]
-		imgs[0] = img.img
-	} else {
 	for i, img := range srcs {
 		if img == nil {
 			continue
 		}
 		imgs[i] = img.img
 	}
-		s = shader.shader
-	}
 
 	i.invalidatePixels()
-	i.img.DrawTriangles(imgs, vertices, indices, mode, dstRegion, srcRegion, subimageOffsets, s, uniforms, evenOdd)
+	i.img.DrawTriangles(imgs, vertices, indices, mode, dstRegion, srcRegion, subimageOffsets, shader.shader, uniforms, evenOdd)
 }
 
 type Shader struct {

internal/graphicscommand/command.go

@@ -328,10 +328,7 @@ func (c *drawTrianglesCommand) Exec(graphicsDriver graphicsdriver.Graphics, inde
 		return nil
 	}
 
-	var shaderID graphicsdriver.ShaderID = graphicsdriver.InvalidShaderID
 	var imgs [graphics.ShaderImageCount]graphicsdriver.ImageID
-	if c.shader != nil {
-		shaderID = c.shader.shader.ID()
 	for i, src := range c.srcs {
 		if src == nil {
 			imgs[i] = graphicsdriver.InvalidImageID
@@ -339,11 +336,8 @@ func (c *drawTrianglesCommand) Exec(graphicsDriver graphicsdriver.Graphics, inde
 		}
 		imgs[i] = src.image.ID()
 	}
-	} else {
-		imgs[0] = c.srcs[0].image.ID()
-	}
 
-	return graphicsDriver.DrawTriangles(c.dst.image.ID(), imgs, c.offsets, shaderID, c.nindices, indexOffset, c.mode, c.dstRegion, c.srcRegion, c.uniforms, c.evenOdd)
+	return graphicsDriver.DrawTriangles(c.dst.image.ID(), imgs, c.offsets, c.shader.shader.ID(), c.nindices, indexOffset, c.mode, c.dstRegion, c.srcRegion, c.uniforms, c.evenOdd)
 }
 
 func (c *drawTrianglesCommand) numVertices() int {

internal/graphicscommand/image.go

@@ -128,14 +128,6 @@ func (i *Image) InternalSize() (int, int) {
 // If the source image is not specified, i.e., src is nil and there is no image in the uniform variables, the
 // elements for the source image are not used.
 func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, offsets [graphics.ShaderImageCount - 1][2]float32, vertices []float32, indices []uint16, mode graphicsdriver.CompositeMode, dstRegion, srcRegion graphicsdriver.Region, shader *Shader, uniforms [][]float32, evenOdd bool) {
-	if shader == nil {
-		// Fast path for rendering without a shader (#1355).
-		img := srcs[0]
-		if img.screen {
-			panic("graphicscommand: the screen image cannot be the rendering source")
-		}
-		img.resolveBufferedWritePixels()
-	} else {
 	for _, src := range srcs {
 		if src == nil {
 			continue
@@ -145,7 +137,6 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, offsets [g
 		}
 		src.resolveBufferedWritePixels()
 	}
-	}
 	i.resolveBufferedWritePixels()
 
 	theCommandQueue.EnqueueDrawTrianglesCommand(i, srcs, offsets, vertices, indices, mode, dstRegion, srcRegion, shader, uniforms, evenOdd)

internal/restorable/image.go

@@ -387,21 +387,14 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageCount]*Image, offsets [g
 		i.appendDrawTrianglesHistory(srcs, offsets, vertices, indices, mode, dstRegion, srcRegion, shader, uniforms, evenOdd)
 	}
 
-	var s *graphicscommand.Shader
 	var imgs [graphics.ShaderImageCount]*graphicscommand.Image
-	if shader == nil {
-		// Fast path for rendering without a shader (#1355).
-		imgs[0] = srcs[0].image
-	} else {
 	for i, src := range srcs {
 		if src == nil {
 			continue
 		}
 		imgs[i] = src.image
 	}
-		s = shader.shader
+	i.image.DrawTriangles(imgs, offsets, vertices, indices, mode, dstRegion, srcRegion, shader.shader, uniforms, evenOdd)
-	}
-	i.image.DrawTriangles(imgs, offsets, vertices, indices, mode, dstRegion, srcRegion, s, uniforms, evenOdd)
 }
 
 // appendDrawTrianglesHistory appends a draw-image history item to the image.