Right now, we use only the SDL library without any OpenGL, so we will declare the iCanvas interface to allow immediate, but not always fast, rendering of geometric primitives and avoid creating the GLVertexArray instances described in the previous chapter. Later, we might provide a different iCanvas implementation to switch to another renderer:
class iCanvas: public iIntrusiveCounter
{
public:The first two methods set the current rendering color specified as a triple of RGB integers or a 4-dimensional vector, which contains an additional alpha transparency value:
virtual void SetColor( int R, int G, int B ) = 0; virtual void SetColor( const ivec4& C ) = 0;
The Clear() method clears the screen rendering surface:
virtual void Clear() = 0;
The Rect() and Line() methods render a rectangle and a line respectively, as their names suggest:
virtual void Rect( int X, int Y,
int W, int H, bool Filled ) = 0;
virtual void Line( int X1, int Y1, int X2, int Y2 ) = 0;The texture-related...