examples/shader: Always use 1 for an alpha

This is necessary to keep the color pre-multiplied

examples/shader/water.go

@@ -32,11 +32,11 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	xoffset := (4 / srcsize.x) * cos(Time*3+texCoord.y*200)
 	yoffset := (20 / srcsize.y) * (1.0 + cos(Time*3+texCoord.y*50))
 	bordertex := border / srcsize.y
-	clr := vec4(image2TextureBoundsAt(vec2(
+	clr := image2TextureBoundsAt(vec2(
 		texCoord.x+xoffset,
 		-(texCoord.y+yoffset-rorigin.y)+bordertex*2+rorigin.y,
-	)))
+	)).rgb
 
-	overlay := vec4(0.5, 1, 1, 1)
+	overlay := vec3(0.5, 1, 1)
-	return mix(clr, overlay, 0.25)
+	return vec4(mix(clr, overlay, 0.25), 1)
 }

examples/shader/water_go.go

@@ -2,4 +2,4 @@
 
 package main
 
-var water_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\nvar ScreenSize vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\tborder := ScreenSize.y*0.6 + 4*cos(Time*3+texCoord.y*200)\n\tif position.y < border {\n\t\treturn image2TextureAt(texCoord)\n\t}\n\n\tsrcsize := imageSrcTextureSize()\n\trorigin, rsize := imageSrcTextureSourceRegion()\n\n\txoffset := (4 / srcsize.x) * cos(Time*3+texCoord.y*200)\n\tyoffset := (20 / srcsize.y) * (1.0 + cos(Time*3+texCoord.y*50))\n\tbordertex := border / srcsize.y\n\tclr := vec4(image2TextureBoundsAt(vec2(\n\t\ttexCoord.x+xoffset,\n\t\t-(texCoord.y+yoffset-rorigin.y)+bordertex*2+rorigin.y,\n\t)))\n\n\toverlay := vec4(0.5, 1, 1, 1)\n\treturn mix(clr, overlay, 0.25)\n}\n")
+var water_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\nvar ScreenSize vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\tborder := ScreenSize.y*0.6 + 4*cos(Time*3+texCoord.y*200)\n\tif position.y < border {\n\t\treturn image2TextureAt(texCoord)\n\t}\n\n\tsrcsize := imageSrcTextureSize()\n\trorigin, rsize := imageSrcTextureSourceRegion()\n\n\txoffset := (4 / srcsize.x) * cos(Time*3+texCoord.y*200)\n\tyoffset := (20 / srcsize.y) * (1.0 + cos(Time*3+texCoord.y*50))\n\tbordertex := border / srcsize.y\n\tclr := image2TextureBoundsAt(vec2(\n\t\ttexCoord.x+xoffset,\n\t\t-(texCoord.y+yoffset-rorigin.y)+bordertex*2+rorigin.y,\n\t)).rgb\n\n\toverlay := vec3(0.5, 1, 1)\n\treturn vec4(mix(clr, overlay, 0.25), 1)\n}\n")