1 files changed, 76 insertions, 0 deletions
diff --git a/_shared/2d/shader.js b/_shared/2d/shader.js
new file mode 100644
index 0000000..7e85a9e
--- /dev/null
+++ b/_shared/2d/shader.js
@@ -0,0 +1,76 @@
+function loadShader(pGl, pShaderType, pShaderSource) {
+    const lShader = pGl.createShader(pShaderType);
+    pGl.shaderSource(lShader, pShaderSource);
+    pGl.compileShader(lShader);
+    if (!pGl.getShaderParameter(lShader, pGl.COMPILE_STATUS)) {
+      alert('An error occurred compiling the shaders: ' + pGl.getShaderInfoLog(lShader));
+      pGl.deleteShader(lShader);
+      return null;
+    }
+  
+    return lShader;
+}
+
+function loadOrthographicShader(pGl) {
+    var lVertex, lFragment;
+
+    function lLoadShaders() {
+        const lVertexShader = loadShader(pGl, pGl.VERTEX_SHADER, lVertex);
+        const lFragmentShader = loadShader(pGl, pGl.FRAGMENT_SHADER, lFragment);
+
+        const lShaderProgram = pGl.createProgram();
+        pGl.attachShader(lShaderProgram, lVertexShader);
+        pGl.attachShader(lShaderProgram, lFragmentShader);
+        pGl.linkProgram(lShaderProgram);
+
+        if (!pGl.getProgramParameter(lShaderProgram, pGl.LINK_STATUS)) {
+            alert('Unable to initialize the shader program: ' + pGl.getProgramInfoLog(lShaderProgram));
+            return null;
+        }
+
+        var lRetval = {
+            program: lShaderProgram,
+            attributeLocations: {
+                position: pGl.getAttribLocation(lShaderProgram, 'position'),
+                color: pGl.getAttribLocation(lShaderProgram, 'color')
+            },
+            uniformLocations: {
+                projection: pGl.getUniformLocation(lShaderProgram, 'projection'),
+                model: pGl.getUniformLocation(lShaderProgram, 'model')
+            }
+        };
+
+        lRetval.renderShape = function(pShape) {
+            pGl.uniformMatrix4fv(lRetval.uniformLocations.model, false, pShape.model);
+            pGl.bindBuffer(pGl.ARRAY_BUFFER, pShape.buffer);
+            {
+                pGl.enableVertexAttribArray(lRetval.attributeLocations.position);
+                pGl.vertexAttribPointer(lRetval.attributeLocations.position, 2, pGl.FLOAT, false, BYTES_PER_FLOAT * 6, 0);
+
+                pGl.enableVertexAttribArray(lRetval.attributeLocations.color);
+                pGl.vertexAttribPointer(lRetval.attributeLocations.color, 4, pGl.FLOAT, false, BYTES_PER_FLOAT * 6, BYTES_PER_FLOAT * 2);
+            }
+
+            pGl.drawArrays(pGl.TRIANGLES, 0, pShape.vertexCount);
+        }
+
+        return lRetval;
+    }
+
+    return fetch('/_shared/2d/shaders/orthographic.vert').then(function(pResponse) {
+        if (pResponse.status === 200) {
+            return pResponse.text().then(function(pShader) {
+                lVertex = pShader;
+
+                return fetch('/_shared/2d/shaders/orthographic.frag').then(function(pResponse) {
+                    if (pResponse.status === 200) {
+                        return pResponse.text().then(function(pShader) {
+                            lFragment = pShader;
+                            return lLoadShaders();
+                        });
+                    }
+                });
+            });
+        }
+    });
+}
+\ No newline at end of file