shader: Rename viewportSize to textureDstSize

Updates #1239

examples/shader/default.go

@@ -19,10 +19,8 @@ package main
 var Time float
 var Cursor vec2
 
-// viewportSize is a predefined function.
-
 func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
-	pos := position.xy/viewportSize() + Cursor/viewportSize()/4
+	pos := position.xy/textureDstSize() + Cursor/textureDstSize()/4
 	clr := 0.0
 	clr += sin(pos.x*cos(Time/15)*80) + cos(pos.y*cos(Time/15)*10)
 	clr += sin(pos.y*sin(Time/10)*40) + cos(pos.x*sin(Time/25)*40)

examples/shader/default_go.go

@@ -3,4 +3,4 @@
 
 package main
 
-var default_go = []byte("// Copyright 2020 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\n// +build ignore\n\npackage main\n\nvar Time float\nvar Cursor vec2\n\n// viewportSize is a predefined function.\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\tpos := position.xy/viewportSize() + Cursor/viewportSize()/4\n\tclr := 0.0\n\tclr += sin(pos.x*cos(Time/15)*80) + cos(pos.y*cos(Time/15)*10)\n\tclr += sin(pos.y*sin(Time/10)*40) + cos(pos.x*sin(Time/25)*40)\n\tclr += sin(pos.x*sin(Time/5)*10) + sin(pos.y*sin(Time/35)*80)\n\tclr *= sin(Time/10) * 0.5\n\treturn vec4(clr, clr*0.5, sin(clr+Time/3)*0.75, 1)\n}\n")
+var default_go = []byte("// Copyright 2020 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\n// +build ignore\n\npackage main\n\nvar Time float\nvar Cursor vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\tpos := position.xy/textureDstSize() + Cursor/textureDstSize()/4\n\tclr := 0.0\n\tclr += sin(pos.x*cos(Time/15)*80) + cos(pos.y*cos(Time/15)*10)\n\tclr += sin(pos.y*sin(Time/10)*40) + cos(pos.x*sin(Time/25)*40)\n\tclr += sin(pos.x*sin(Time/5)*10) + sin(pos.y*sin(Time/35)*80)\n\tclr *= sin(Time/10) * 0.5\n\treturn vec4(clr, clr*0.5, sin(clr+Time/3)*0.75, 1)\n}\n")

shader.go

@@ -29,16 +29,16 @@ var shaderSuffix string
 
 func init() {
 	shaderSuffix = `
-var __viewportSize vec2
+var __textureDstSize vec2
 
-func viewportSize() vec2 {
+func textureDstSize() vec2 {
-	return __viewportSize
+	return __textureDstSize
 }
 
 func __vertex(position vec2, texCoord vec2, color vec4) (vec4, vec2, vec4) {
 	return mat4(
-		2/viewportSize().x, 0, 0, 0,
+		2/textureDstSize().x, 0, 0, 0,
-		0, 2/viewportSize().y, 0, 0,
+		0, 2/textureDstSize().y, 0, 0,
 		0, 0, 1, 0,
 		-1, -1, 0, 1,
 	) * vec4(position, 0, 1), texCoord, color