Graphics Reference
In-Depth Information
On Android and iOS, we provide projects compatible with those platforms
(Eclipse ADT and Xcode). As of this writing, many devices support OpenGL
ES 3.0, including iPhone 5s, Google Nexus 4 and 7, Nexus 10, HTC One,
LG G2, Samsung Galaxy S4 (Snapdragon), and Samsung Galaxy Note 3. On
iOS7, you can run the OpenGL ES 3.0 examples on your Mac using the iOS
Simulator. On Android, you will need a device compatible with OpenGL
ES 3.0 to run the samples. Details on building the sample code for each
platform are provided in Chapter 16, “OpenGL ES Platforms.”
Let's look at the full source code for our Hello Triangle example program,
which is listed in Example 2-1. Those readers who are familiar with
fixed-function desktop OpenGL will probably think this is a lot of code
just to draw a simple triangle. Those of you who are not familiar with
desktop OpenGL will also probably think this is a lot of code just to draw
a triangle! Remember, OpenGL ES 3.0 is fully shader based, which means
you cannot draw any geometry without having the appropriate shaders
loaded and bound. This means that more setup code is required to render
than in desktop OpenGL using fixed-function processing.
Example 2-1
Hello_Triangle.c Example
#include "esUtil.h"
typedef struct
{
// Handle to a program object
GLuint programObject;
} UserData;
///
// Create a shader object, load the shader source, and
// compile the shader
//
GLuint LoadShader ( GLenum type, const char *shaderSrc )
{
GLuint shader;
GLint compiled;
// Create the shader object
shader = glCreateShader ( type );
(continues)
