disegna una trama pixelata

Question

Ho una bitmap che desidero disegnare ingrandita e con bordi diritti definiti tra i pixel.

Ho provato a fissare il filtro MAG più vicina:

gl.bindTexture(gl.TEXTURE_2D,this.tex); 
gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.NEAREST); 
gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MAG_FILTER,gl.NEAREST); 
... 
gl.drawArrays(gl.TRIANGLES,0,6); // draw the texture 

Tuttavia, quando disegno che i pixel sanguinare insieme:

Questo è WebGL così ho shaders. Il mio codice degli shader è super-semplice:

Vertex Shader:

... 
attribute vec2 texCoord; 
varying vec2 texel; 
void main() { 
    texel = texCoord; 
    ... 

E frammento di shader:

... 
varying vec2 texel; 
uniform sampler2D texture; 
void main() { 
    vec4 fragColour = texture2D(texture,texel); 
    ... 

Ecco un frammento più grande del relativo codice:

map = { 
    vbo: gl.createBuffer(), 
    tex: gl.createTexture(), 
    program: createProgram(
     "precision mediump float;\n"+ 
     "uniform mat4 mvMatrix, pMatrix;\n"+ 
     "attribute vec3 vertex;\n"+ 
     "attribute vec2 texCoord;\n"+ 
     "varying vec2 texel;\n"+ 
     "void main() {\n"+ 
     " texel = texCoord;\n"+ 
     " gl_Position = pMatrix * mvMatrix * vec4(vertex,1.0);\n"+ 
     "}\n", 
     "precision mediump float;\n"+ 
     "uniform vec4 colour;\n"+ 
     "uniform float fogDensity;\n"+ 
     "uniform vec4 fogColour;\n"+ 
     "varying vec2 texel;\n"+ 
     "uniform sampler2D texture;\n"+ 
     "const float LOG2 = 1.442695;\n"+ 
     "void main() {\n"+ 
     " float z = gl_FragCoord.z/gl_FragCoord.w;\n"+ 
     " float fogFactor = exp2(-fogDensity*fogDensity*z*z*LOG2);\n"+ 
     " fogFactor = clamp(fogFactor,0.0,1.0);\n"+ 
     " vec4 fragColour = texture2D(texture,texel) * colour;\n"+ 
     " gl_FragColor = mix(fogColour,fragColour,fogFactor);\n"+ 
     "}\n", 
     ["mvMatrix","pMatrix","colour","fogDensity","fogColour","texture"], 
     ["vertex","texCoord"]), 
    plane: [[0,0,0],[0,1,0]], 
    init: function(w,h) { 
     this.w = w; 
     this.h = h; 
     var vertices = [ 
      w,0,0, 1,0, 
      0,0,0, 0,0, 
      w,0,h, 1,1, 
      w,0,h, 1,1, 
      0,0,0, 0,0, 
      0,0,h, 0,1, 
     ]; 
     gl.bindBuffer(gl.ARRAY_BUFFER,this.vbo); 
     gl.bufferData(gl.ARRAY_BUFFER,new Float32Array(vertices),gl.STATIC_DRAW); 
     gl.bindBuffer(gl.ARRAY_BUFFER,null); 
     this._mapArrayBuffer = new ArrayBuffer(w*h*4); 
     this._mapByteBuffer = new Uint8Array(this._mapArrayBuffer); 
     this.map = new Uint32Array(this._mapArrayBuffer); 
     for(var i=0; i<w*h; i++) // test data: red and green pixels 
      this.map[i] = Math.random()>0.5? 0xff000080: 0xff008000; 
     createTexture(this.tex,w,h,this._mapByteBuffer,true); 
    }, 
    draw: function() { 
     var program = this.program; 
     gl.useProgram(program); 
     gl.uniformMatrix4fv(program.pMatrix,false,camera.pMatrix); 
     gl.uniformMatrix4fv(program.mvMatrix,false,camera.mvMatrix); 
     gl.uniform4f(program.colour,1,1,1,1); 
     gl.uniform4f(program.fogColour,1,1,1,1); 
     gl.uniform1f(program.fogDensity,0.03); 
     gl.bindTexture(gl.TEXTURE_2D,this.tex); 
     gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.NEAREST); 
     gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MAG_FILTER,gl.NEAREST); 
     gl.bindBuffer(gl.ARRAY_BUFFER,this.vbo); 
     gl.enableVertexAttribArray(program.vertex); 
     gl.vertexAttribPointer(program.vertex,3,gl.FLOAT,false,5*4,0); 
     gl.enableVertexAttribArray(program.texCoord); 
     gl.vertexAttribPointer(program.texCoord,2,gl.FLOAT,false,5*4,3*4); 
     gl.drawArrays(gl.TRIANGLES,0,6); 
     gl.disableVertexAttribArray(program.texCoord); 
     gl.disableVertexAttribArray(program.vertex); 
     gl.bindBuffer(gl.ARRAY_BUFFER,null); 
     gl.bindTexture(gl.TEXTURE_2D,null); 
     gl.useProgram(null); 
    }, 
}; 

function createTexture(tex,width,height,data,noMipMap) { 
    tex = tex || gl.createTexture(); 
    gl.bindTexture(gl.TEXTURE_2D,tex); 
    tex.width = width || data.width; 
    tex.height = height || data.height; 
    if(width != null) 
     gl.texImage2D(gl.TEXTURE_2D,0,gl.RGBA,width,height,0,gl.RGBA,gl.UNSIGNED_BYTE,data || null); 
    else 
     gl.texImage2D(gl.TEXTURE_2D,0,gl.RGBA,gl.RGBA,gl.UNSIGNED_BYTE,data); 
    if(anisotropy) 
     gl.texParameterf(gl.TEXTURE_2D,anisotropic.TEXTURE_MAX_ANISOTROPY_EXT,anisotropy); 
    gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_WRAP_S,gl.CLAMP_TO_EDGE); 
    gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_WRAP_T,gl.CLAMP_TO_EDGE); 
    gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MAG_FILTER,gl.LINEAR); 
    if(!noMipMap && !(tex.width&(tex.width-1)) && !(tex.height&(tex.height-1))) { //pow2 
     gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.LINEAR_MIPMAP_LINEAR); 
     gl.generateMipmap(gl.TEXTURE_2D); 
    } else 
     gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.LINEAR); 
    gl.bindTexture(gl.TEXTURE_2D,null); 
    _textures.push(tex); 
    return tex; 
} 

Answer 1

[SOLVED] Il problema era che stavo abilitando l'anisotropia per la trama. L'anisotropia trionfa gl_NEAREST, a quanto pare. Se si desidera utilizzare gl_NEAREST su una trama, è importante non avere anche un set di anisotropia.