test depth buffer

Author: mikolalysenko

test/depth-buffer.js

@@ -0,0 +1,51 @@
+'use strict'
+
+var tape = require('tape')
+var createContext = require('../index')
+var drawTriangle = require('./util/draw-triangle')
+var makeShader = require('./util/make-program')
+
+tape('depth-buffer', function (t) {
+  var width = 50
+  var height = 50
+  var gl = createContext(width, height)
+
+  var vertex_src = [
+    'attribute vec2 position;',
+    'uniform float depth;',
+    'void main() { gl_Position = vec4(position,depth,1); }'
+  ].join('\n')
+
+  var fragment_src = [
+    'precision mediump float;',
+    'uniform vec4 color;',
+    'void main() { gl_FragColor = color; }'
+  ].join('\n')
+
+  gl.clearColor(0, 0, 0, 0)
+  gl.clearDepth(1)
+  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
+
+  gl.enable(gl.DEPTH_TEST)
+  gl.depthFunc(gl.NOTEQUAL)
+
+  var program = makeShader(gl, vertex_src, fragment_src)
+  gl.useProgram(program)
+  gl.uniform1f(gl.getUniformLocation(program, 'depth'), 0)
+  gl.uniform4f(gl.getUniformLocation(program, 'color'), 1, 0, 0, 1)
+  drawTriangle(gl)
+  gl.uniform1f(gl.getUniformLocation(program, 'depth'), 1)
+  gl.uniform4f(gl.getUniformLocation(program, 'color'), 0, 1, 0, 1)
+  drawTriangle(gl)
+
+  var pixels = new Uint8Array(width * height * 4)
+  gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, pixels)
+  for (var i = 0; i < width * height * 4; i += 4) {
+    t.equals(pixels[i], 0, 'red')
+    t.equals(pixels[i + 1], 255, 'green')
+    t.equals(pixels[i + 2], 0, 'blue')
+    t.equals(pixels[i + 3], 255, 'alpha')
+  }
+
+  t.end()
+})