Fix shaders for WebGL

internal/graphics/internal/shader/program.go

@@ -24,22 +24,21 @@ func initialize(c *opengl.Context) error {
 	const size = 10000
 	const uint16Size = 2
 
-	var err error
-	shaders[shaderVertex].native, err = c.NewShader(c.VertexShader, shaders[shaderVertex].source)
+	shaderVertexNative, err := c.NewShader(c.VertexShader, shader(c, shaderVertex))
 	if err != nil {
 		return err
 	}
-	defer c.DeleteShader(shaders[shaderVertex].native)
+	defer c.DeleteShader(shaderVertexNative)
 
-	shaders[shaderColorMatrix].native, err = c.NewShader(c.FragmentShader, shaders[shaderColorMatrix].source)
+	shaderColorMatrixNative, err := c.NewShader(c.FragmentShader, shader(c, shaderColorMatrix))
 	if err != nil {
 		return err
 	}
-	defer c.DeleteShader(shaders[shaderColorMatrix].native)
+	defer c.DeleteShader(shaderColorMatrixNative)
 
 	shaders := []opengl.Shader{
-		shaders[shaderVertex].native,
-		shaders[shaderColorMatrix].native,
+		shaderVertexNative,
+		shaderColorMatrixNative,
 	}
 	programColorMatrix, err = c.NewProgram(shaders)
 	if err != nil {

internal/graphics/internal/shader/shader.go

@@ -16,13 +16,9 @@ package shader
 
 import (
 	"github.com/hajimehoshi/ebiten/internal/opengl"
+	"strings"
 )
 
-type shader struct {
-	native opengl.Shader
-	source string
-}
-
 type shaderId int
 
 const (
@@ -30,30 +26,37 @@ const (
 	shaderColorMatrix
 )
 
-var shaders = map[shaderId]*shader{
-	shaderVertex: {
-		source: `
-uniform mat4 projection_matrix;
-uniform mat4 modelview_matrix;
-attribute vec2 vertex;
-attribute vec2 tex_coord;
-varying vec2 vertex_out_tex_coord;
+func shader(c *opengl.Context, id shaderId) string {
+	str := shaders[id]
+	if !c.GlslHighpSupported() {
+		str = strings.Replace(str, "highp ", "", -1)
+		str = strings.Replace(str, "lowp ", "", -1)
+	}
+	return str
+}
+
+// TODO: Create version 100 for WebGL
+var shaders = map[shaderId]string{
+	shaderVertex: `
+uniform highp mat4 projection_matrix;
+uniform highp mat4 modelview_matrix;
+attribute highp vec2 vertex;
+attribute highp vec2 tex_coord;
+varying highp vec2 vertex_out_tex_coord;
 
 void main(void) {
   vertex_out_tex_coord = tex_coord;
   gl_Position = projection_matrix * modelview_matrix * vec4(vertex, 0, 1);
 }
 `,
-	},
-	shaderColorMatrix: {
-		source: `
-uniform sampler2D texture;
-uniform mat4 color_matrix;
-uniform vec4 color_matrix_translation;
-varying vec2 vertex_out_tex_coord;
+	shaderColorMatrix: `
+uniform lowp sampler2D texture;
+uniform lowp mat4 color_matrix;
+uniform lowp vec4 color_matrix_translation;
+varying highp vec2 vertex_out_tex_coord;
 
 void main(void) {
-  vec4 color = texture2D(texture, vertex_out_tex_coord);
+  lowp vec4 color = texture2D(texture, vertex_out_tex_coord);
 
   if (color_matrix != mat4(1.0) || color_matrix_translation != vec4(0.0)) {
     // Un-premultiply alpha
@@ -68,5 +71,4 @@ void main(void) {
   gl_FragColor = color;
 }
 `,
-	},
 }

internal/opengl/context.go

@@ -58,7 +58,6 @@ func (c *Context) NewTexture(width, height int, pixels []uint8, filter FilterTyp
 	}
 	gl.PixelStorei(gl.UNPACK_ALIGNMENT, 4)
 	t.Bind(gl.TEXTURE_2D)
-	defer gl.Texture(0).Bind(gl.TEXTURE_2D)
 
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, int(filter))
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, int(filter))
@@ -148,6 +147,10 @@ func (c *Context) DeleteShader(s Shader) {
 	gl.Shader(s).Delete()
 }
 
+func (c *Context) GlslHighpSupported() bool {
+	return false
+}
+
 func (c *Context) NewProgram(shaders []Shader) (Program, error) {
 	p := gl.CreateProgram()
 	if p == 0 {

internal/opengl/context_js.go

@@ -63,7 +63,6 @@ func (c *Context) NewTexture(width, height int, pixels []uint8, filter FilterTyp
 	}
 	gl.PixelStorei(gl.UNPACK_ALIGNMENT, 4)
 	gl.BindTexture(gl.TEXTURE_2D, t)
-	defer gl.BindTexture(gl.TEXTURE_2D, nil)
 
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, int(filter))
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, int(filter))
@@ -71,7 +70,11 @@ func (c *Context) NewTexture(width, height int, pixels []uint8, filter FilterTyp
 	// void texImage2D(GLenum target, GLint level, GLenum internalformat,
 	//     GLsizei width, GLsizei height, GLint border, GLenum format,
 	//     GLenum type, ArrayBufferView? pixels);
-	gl.Call("texImage2D", gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, pixels)
+	var p interface{}
+	if pixels != nil {
+		p = pixels
+	}
+	gl.Call("texImage2D", gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, p)
 
 	return Texture(t), nil
 }
@@ -99,6 +102,11 @@ func (c *Context) DeleteTexture(t Texture) {
 	gl.DeleteTexture(t)
 }
 
+func (c *Context) GlslHighpSupported() bool {
+	gl := c.gl
+	return gl.Call("getShaderPrecisionFormat", gl.FRAGMENT_SHADER, gl.HIGH_FLOAT).Get("precision").Int() != 0
+}
+
 func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 	gl := c.gl
 	f := gl.CreateFramebuffer()