OpenGL vertex attribute helper.

modules/juce_opengl/opengl/juce_OpenGLShaderProgram.cpp

@@ -83,6 +83,12 @@ OpenGLShaderProgram::Uniform::Uniform (const OpenGLShaderProgram& program, const
     jassert (uniformID >= 0);
 }
 
+OpenGLShaderProgram::Attribute::Attribute (const OpenGLShaderProgram& program, const char* name)
+    : attributeID (glGetAttribLocation (program.programID, name))
+{
+    jassert (attributeID >= 0);
+}
+
 void OpenGLShaderProgram::Uniform::set (GLfloat n1) const noexcept                                    { glUniform1f (uniformID, n1); }
 void OpenGLShaderProgram::Uniform::set (GLint n1) const noexcept                                      { glUniform1i (uniformID, n1); }
 void OpenGLShaderProgram::Uniform::set (GLfloat n1, GLfloat n2) const noexcept                        { glUniform2f (uniformID, n1, n2); }

modules/juce_opengl/opengl/juce_OpenGLShaderProgram.h

@@ -101,6 +101,24 @@ public:
         GLint uniformID;
     };
 
+    /** Represents an openGL vertex attribute value.
+        After a program has been linked, you can create Attribute objects to let you
+        set the attributes that your vertex shaders use.
+    */
+    struct Attribute
+    {
+        /** Initialises an attribute.
+            The program must have been successfully linked when this
+            constructor is called.
+        */
+        Attribute (const OpenGLShaderProgram& program, const char* attributeName);
+
+        /** The attribute's ID number.
+            If the uniform couldn't be found, this value will be < 0.
+        */
+        GLint attributeID;
+    };
+
     /** The ID number of the compiled program. */
     GLuint programID;