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POGLKit: [drawing pixels] initializing GLfloat array
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  1. POGLKit: [drawing pixels] initializing GLfloat array
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    copied!<p>I am drawing a pixel using GLKit. I can successfully draw the pixel at (10, 10) coordinates if I have:</p> <pre><code>glClearColor(0.65f, 0.65f, 0.65f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Prepare the effect for rendering [self.effect prepareToDraw]; GLfloat points[] = { 10.0f, 10.0f, }; glClearColor(1.0f, 1.0f, 0.0f, 1.0f); GLuint bufferObjectNameArray; glGenBuffers(1, &amp;bufferObjectNameArray); glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray); glBufferData( GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW); glEnableVertexAttribArray(GLKVertexAttribPosition); glVertexAttribPointer( GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, 2*4, NULL); glDrawArrays(GL_POINTS, 0, 1); </code></pre> <p>But I want to decide at runtime how many and exactly where I want to draw pixels, so I tried this but it is drawing pixel at (10, 0), something's wrong here:</p> <pre><code>glClearColor(0.65f, 0.65f, 0.65f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Prepare the effect for rendering [self.effect prepareToDraw]; GLfloat *points = (GLfloat*)malloc(sizeof(GLfloat) * 2); for (int i=0; i&lt;2; i++) { points[i] = 10.0f; } glClearColor(1.0f, 1.0f, 0.0f, 1.0f); GLuint bufferObjectNameArray; glGenBuffers(1, &amp;bufferObjectNameArray); glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray); glBufferData( GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW); glEnableVertexAttribArray(GLKVertexAttribPosition); glVertexAttribPointer( GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, 2*4, NULL); glDrawArrays(GL_POINTS, 0, 1); </code></pre> <p>Kindly help me out.</p> <p>Edit: <strong>Problem</strong> Actually the problem is: I can't figure out what is the difference between:</p> <pre><code>GLfloat points[] = { 10.0f, 10.0f, }; </code></pre> <p>AND</p> <pre><code>GLfloat *points = (GLfloat*)malloc(sizeof(GLfloat) * 2); for (int i=0; i&lt;2; i++) { points[i] = 10.0f; } </code></pre>
 

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