From 98d7d6cb702af2708f20e7cf16ee10a9f71b578a Mon Sep 17 00:00:00 2001
From: Matthew Kosarek <matthew.kosarek@vention.cc>
Date: Sat, 13 Mar 2021 15:43:56 -0500
Subject: My First WASM application is rendering a triangle on the frontend

---
 frontend/_wasm/Shader.cpp | 61 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 frontend/_wasm/Shader.cpp

(limited to 'frontend/_wasm/Shader.cpp')

diff --git a/frontend/_wasm/Shader.cpp b/frontend/_wasm/Shader.cpp
new file mode 100644
index 0000000..5f2b00e
--- /dev/null
+++ b/frontend/_wasm/Shader.cpp
@@ -0,0 +1,61 @@
+#include "Shader.h"
+#include <string>
+
+GLuint loadIndividualShader(GLenum shaderType, const GLchar* cCode) {
+    GLuint shader = glCreateShader(shaderType);
+    glShaderSource(shader, 1, &cCode, 0);
+    glCompileShader(shader);
+    GLint success;
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        GLchar infoLog[512];
+        glGetShaderInfoLog(shader, 512, 0, infoLog);
+		printf("Failed to load shader: %s, Shader =%s\n", infoLog, cCode);
+        return 0;
+    }
+    
+    return shader;
+}
+
+void attachShaders(Shader& retVal, const GLchar* vertexShader, const GLchar* fragmentShader) {
+    GLuint vertex = 0, fragment = 0, geometry = 0;
+    if (vertexShader) {
+        vertex = loadIndividualShader(GL_VERTEX_SHADER, vertexShader);
+        glAttachShader(retVal, vertex);
+    }
+
+    if (fragmentShader) {
+        fragment = loadIndividualShader(GL_FRAGMENT_SHADER, fragmentShader);
+        glAttachShader(retVal, fragment);
+    }
+
+    glLinkProgram(retVal);
+    GLint isLinked = 0;
+    glGetProgramiv(retVal, GL_LINK_STATUS, (int*)&isLinked);
+    if (isLinked == GL_FALSE) {
+        GLint maxLength = 0;
+        glGetProgramiv(retVal, GL_INFO_LOG_LENGTH, &maxLength);
+
+        // The maxLength includes the NULL character
+        GLchar* infoLog = new GLchar[maxLength];
+        glGetProgramInfoLog(retVal, maxLength, &maxLength, infoLog);
+        glDeleteProgram(retVal);
+        printf("Error. Could not initialize shader with vertex=%s, error=%s\n", vertexShader, infoLog);
+        delete []infoLog;
+    }
+
+    if (vertexShader)
+        glDeleteShader(vertex);
+    if (fragmentShader)
+        glDeleteShader(fragment);
+}
+
+Shader loadShader(const GLchar* vertexShader, const GLchar* fragmentShader) {
+    Shader retVal;
+    retVal = glCreateProgram();
+
+    attachShaders(retVal, vertexShader, fragmentShader);
+    useShader(retVal);
+
+    return retVal;
+}
-- 
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