Added support for rendering using an index buffer object.

kromenak · Sep 22, 2017 · 5f1d856 · 5f1d856
1 parent ad42eb0
commit 5f1d856
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Showing 3 changed files with 30 additions and 86 deletions.
diff --git a/Source/GLVertexArray.cpp b/Source/GLVertexArray.cpp
@@ -18,13 +18,19 @@ GLVertexArray::GLVertexArray(const GLfloat* vertPositions, int vertPositionsCoun
     glBindBuffer(GL_ARRAY_BUFFER, mVBO);
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
 
-    //glGenBuffers(1, &ibo);
-    //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
-    //glBufferData(GL_ELEMENT_ARRAY_BUFFER, 24 * sizeof(GLushort), cube_elements, GL_STATIC_DRAW);
-
     mVertexCount = vertPositionsCount / 3;
 }
 
+GLVertexArray::GLVertexArray(const GLfloat* vertPositions, int vertPositionsCount,
+                             const GLushort* indexes, int indexesCount)
+: GLVertexArray(vertPositions, vertPositionsCount)
+{
+    glGenBuffers(1, &mIBO);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIBO);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexesCount * sizeof(GLushort), indexes, GL_STATIC_DRAW);
+    mIndexesCount = indexesCount;
+}
+
 GLVertexArray::~GLVertexArray()
 {
     if(mVBO != GL_NONE)
@@ -44,14 +50,15 @@ GLVertexArray::~GLVertexArray()
 void GLVertexArray::Activate()
 {
     glBindVertexArray(mVAO);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIBO);
 }
 
 void GLVertexArray::Draw()
 {
     Activate();
     if(mIBO != GL_NONE)
     {
-        //TODO: Draw using indexes.
+        glDrawElements(GL_TRIANGLES, mIndexesCount, GL_UNSIGNED_SHORT, (void*)0);
     }
     else
     {

diff --git a/Source/GLVertexArray.h b/Source/GLVertexArray.h
@@ -13,6 +13,8 @@ class GLVertexArray
 {
 public:
     GLVertexArray(const GLfloat* vertPositions, int vertPositionsCount);
+    GLVertexArray(const GLfloat* vertPositions, int vertPositionsCount,
+                  const GLushort* indexes, int indexesCount);
     ~GLVertexArray();
 
     void Activate();
@@ -24,4 +26,5 @@ class GLVertexArray
     GLuint mIBO = GL_NONE;
 
     int mVertexCount = 0;
+    int mIndexesCount = 0;
 };
diff --git a/Source/SDLRenderer.cpp b/Source/SDLRenderer.cpp
@@ -19,17 +19,23 @@ GLfloat triangle_vertices[] = {
     -0.5f, -0.5f,  0.0f
 };
 
+GLfloat triange_colors[] {
+    1.0f, 0.0f, 0.0f, 1.0f,
+    0.0f, 1.0f, 0.0f, 1.0f,
+    0.0f, 0.0f, 1.0f, 1.0f
+};
+
 GLfloat cube_vertices[] = {
     // front
-    -1.0, -1.0,  1.0,
-    1.0, -1.0,  1.0,
-    1.0,  1.0,  1.0,
-    -1.0,  1.0,  1.0,
+    -0.5, -0.5,  0.5,
+    0.5, -0.5, 0.5,
+    0.5,  0.5,  0.5,
+    -0.5,  0.5,  0.5,
     // back
-    -1.0, -1.0, -1.0,
-    1.0, -1.0, -1.0,
-    1.0,  1.0, -1.0,
-    -1.0,  1.0, -1.0
+    -0.5, -0.5, -0.5,
+    0.5, -0.5, -0.5,
+    0.5,  0.5, -0.5,
+    -0.5,  0.5, -0.5
 };
 
 GLfloat cube_colors[] = {
@@ -119,6 +125,7 @@ bool SDLRenderer::Initialize()
         return false;
     }
     mVertArray = new GLVertexArray(triangle_vertices, 9);
+    //mVertArray = new GLVertexArray(cube_vertices, 24, cube_elements, 36);
 
     // Init succeeded!
     return true;
@@ -164,76 +171,3 @@ void SDLRenderer::Present()
 {
     SDL_GL_SwapWindow(mWindow);
 }
-
-GLuint SDLRenderer::LoadAndCompileShaderFromFile(const char* filePath, GLuint shaderType)
-{
-    // Open the file, but freak out if not valid.
-    std::ifstream file(filePath);
-    if(!file.good())
-    {
-        std::cout << "Couldn't open shader file for loading: " << filePath << std::endl;
-        return GL_NONE;
-    }
-
-    // Read the file contents into a char buffer.
-    // Important to read to intermediate std::string first!
-    // Doesn't read correctly without that bit.
-    std::stringstream buffer;
-    buffer << file.rdbuf();
-    std::string fileContentsStr = buffer.str();
-    const char* fileContents = fileContentsStr.c_str();
-
-    // Create shader, load file contents into it, and compile it.
-    GLuint shader = glCreateShader(shaderType);
-    glShaderSource(shader, 1, &fileContents, nullptr);
-    glCompileShader(shader);
-    return shader;
-}
-
-bool SDLRenderer::IsShaderCompiled(GLuint shader)
-{
-    // Ask GL whether compile succeeded for this shader.
-    GLint compileSucceeded = 0;
-    glGetShaderiv(shader, GL_COMPILE_STATUS, &compileSucceeded);
-
-    // If not, we'll output the error log and fail.
-    if(compileSucceeded == GL_FALSE)
-    {
-        GLint errorLength = 0;
-        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &errorLength);
-
-        GLchar* errorLog = new GLchar[errorLength];
-        glGetShaderInfoLog(shader, errorLength, &errorLength, errorLog);
-
-        std::cout << "Error compiling shader: " << errorLog << std::endl;
-        delete[] errorLog;
-        return false;
-    }
-
-    // GL reports the compilation was successful!
-    return true;
-}
-
-bool SDLRenderer::IsProgramLinked(GLuint program)
-{
-    // Ask GL whether link succeeded for this program.
-    GLint linkSucceeded = 0;
-    glGetProgramiv(program, GL_LINK_STATUS, &linkSucceeded);
-
-    // If not, we'll output the error log and fail.
-    if(linkSucceeded == GL_FALSE)
-    {
-        GLint errorLength = 0;
-        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &errorLength);
-
-        GLchar* errorLog = new GLchar[errorLength];
-        glGetProgramInfoLog(program, errorLength, &errorLength, errorLog);
-
-        std::cout << "Error linking shader program: " << errorLog << std::endl;
-        delete[] errorLog;
-        return false;
-    }
-
-    // GL reports the linking was successful!
-    return true;
-}