source: trunk/src/gl/gl_context.cc @ 38

// Copyright (C) 2012-2013 Kornel Kisielewicz
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh

#include "nv/gl/gl_context.hh"

#include "nv/gl/gl_enum.hh"
#include "nv/lib/gl.hh"

using namespace nv;

void gl_context::clear( const clear_state& cs )
{
        // apply_framebuffer
        apply_scissor_test( cs.scissor_test );
        apply_color_mask( cs.color_mask );
        apply_depth_mask( cs.depth_mask );
        // stencil_mask_separate

        if ( m_clear_color != cs.color )
        {
                glClearColor( cs.color.r, cs.color.g, cs.color.b, cs.color.a );
                m_clear_color = cs.color;
        }

        if ( m_clear_depth != cs.depth )
        {
                glClearDepth( cs.depth );
                m_clear_depth = cs.depth;
        }

        if ( m_clear_stencil != cs.stencil )
        {
                glClearStencil( cs.stencil );
                m_clear_stencil = cs.stencil;
        }

        glClear( cs.buffers );
}

const ivec4& gl_context::get_viewport()
{
        return m_viewport;
}

void gl_context::set_viewport( const ivec4& viewport )
{
        if ( viewport.z < 0 || viewport.w < 0 )
        {
                throw new logic_error("viewport width and height must be greater than zero!");
        }

        m_viewport = viewport;
        glViewport( viewport.x, viewport.y, viewport.z, viewport.w );
}

void gl_context::enable( unsigned int what, bool value )
{
        if ( value )
        {
                glEnable( what );
        }
        else
        {
                glDisable( what );
        }
}

void gl_context::apply_stencil_test( const stencil_test& stencil )
{
        if ( m_render_state.stencil_test.enabled != stencil.enabled )
        {
                enable( GL_STENCIL_TEST, stencil.enabled );
                m_render_state.stencil_test.enabled = stencil.enabled;
        }

        if ( stencil.enabled )
        {
                apply_stencil_face( GL_FRONT, m_render_state.stencil_test.front_face, stencil.front_face );
                apply_stencil_face( GL_BACK,  m_render_state.stencil_test.back_face,  stencil.back_face );
        }
}

void gl_context::apply_stencil_face( int face, stencil_test_face& stencil, const stencil_test_face& new_stencil )
{
        if (( stencil.op_fail       != new_stencil.op_fail       ) ||
                ( stencil.op_depth_fail != new_stencil.op_depth_fail ) ||
                ( stencil.op_depth_pass != new_stencil.op_depth_pass ) )
        {
                glStencilOpSeparate( face,
                        stencil_operation_to_enum( new_stencil.op_fail ),
                        stencil_operation_to_enum( new_stencil.op_depth_fail ),
                        stencil_operation_to_enum( new_stencil.op_depth_pass )
                );

                stencil.op_fail       = new_stencil.op_fail;
                stencil.op_depth_fail = new_stencil.op_depth_fail;
                stencil.op_depth_pass = new_stencil.op_depth_pass;
        }

        if (( stencil.function  != new_stencil.function ) ||
                ( stencil.ref_value != new_stencil.ref_value ) ||
                ( stencil.mask      != new_stencil.mask ))
        {
                glStencilFuncSeparate( face,
                        stencil_function_to_enum( new_stencil.function ),
                        new_stencil.ref_value,
                        new_stencil.mask
                );

                stencil.function  = new_stencil.function;
                stencil.ref_value = new_stencil.ref_value;
                stencil.mask      = new_stencil.mask;
        }
}

void gl_context::apply_scissor_test( const scissor_test& scissor )
{
        if ( m_render_state.scissor_test.enabled != scissor.enabled )
        {
                enable( GL_SCISSOR_TEST, scissor.enabled );
                m_render_state.scissor_test.enabled = scissor.enabled;
        }

        if ( scissor.dim.x < 0 || scissor.dim.y < 0 )
        {
                throw new logic_error("scissor_test.rect width and height must be greater than zero!");
        }

        if ( scissor.enabled )
        {
                if ( m_render_state.scissor_test.dim != scissor.dim || m_render_state.scissor_test.pos != scissor.pos )
                {
                        glScissor( 
                                scissor.pos.x, scissor.pos.y, 
                                scissor.dim.x, scissor.dim.y
                        );
                        m_render_state.scissor_test.dim = scissor.dim;
                        m_render_state.scissor_test.pos = scissor.pos;
                }
        }
}

void gl_context::apply_depth_test( const depth_test& depth )
{
        if ( m_render_state.depth_test.enabled != depth.enabled )
        {
                enable( GL_DEPTH_TEST, depth.enabled );
                m_render_state.depth_test.enabled = depth.enabled;
        }

        if ( depth.enabled )
        {
                if ( m_render_state.depth_test.function != depth.function )
                {
                        glDepthFunc( depth_state_function_to_enum( depth.function ) );
                        m_render_state.depth_test.function = depth.function;
                }
        }
}

void gl_context::apply_depth_mask( bool mask )
{
        if ( m_render_state.depth_mask != mask )
        {
                glDepthMask( mask );
                m_render_state.depth_mask = mask;
        }
}

void gl_context::apply_depth_range( const depth_range& range )
{
        if ( range.near < 0.0 || range.near > 1.0 )
        {
                throw new logic_error("render_state.depth_range.near must be between zero and one!");
        }
        if ( range.far < 0.0 || range.far > 1.0 )
        {
                throw new logic_error("render_state.depth_range.far must be between zero and one!");
        }

        if ((m_render_state.depth_range.far  != range.far) ||
                (m_render_state.depth_range.near != range.near))
        {
                glDepthRange( range.near, range.far );

                m_render_state.depth_range.far  = range.far;
                m_render_state.depth_range.near = range.near;
        }
}

void gl_context::apply_color_mask( const color_mask& mask )
{
        if ( m_render_state.color_mask != mask )
        {
                glColorMask( mask.red, mask.green, mask.blue, mask.alpha );
                m_render_state.color_mask = mask;
        }
}

void gl_context::apply_blending( const blending& blend )
{
        if ( m_render_state.blending.enabled != blend.enabled )
        {
                enable( GL_BLEND, blend.enabled );
                m_render_state.blending.enabled = blend.enabled;
        }

        if ( blend.enabled )
        {
                if ((m_render_state.blending.src_rgb_factor   != blend.src_rgb_factor ) ||
                        (m_render_state.blending.dst_rgb_factor   != blend.dst_rgb_factor ) ||
                        (m_render_state.blending.src_alpha_factor != blend.src_alpha_factor ) ||
                        (m_render_state.blending.dst_alpha_factor != blend.dst_alpha_factor ))
                {
                        glBlendFuncSeparate(
                                blending_factor_to_enum( blend.src_rgb_factor ),
                                blending_factor_to_enum( blend.dst_rgb_factor ),
                                blending_factor_to_enum( blend.src_alpha_factor ),
                                blending_factor_to_enum( blend.dst_alpha_factor )
                        );

                        m_render_state.blending.src_rgb_factor   = blend.src_rgb_factor;
                        m_render_state.blending.dst_rgb_factor   = blend.dst_rgb_factor;
                        m_render_state.blending.src_alpha_factor = blend.src_alpha_factor;
                        m_render_state.blending.dst_alpha_factor = blend.dst_alpha_factor; 
                }

                if ((m_render_state.blending.rgb_equation   != blend.rgb_equation ) ||
                        (m_render_state.blending.alpha_equation != blend.alpha_equation ))
                {
                        glBlendEquationSeparate(
                                blending_equation_to_enum( blend.rgb_equation ),
                                blending_equation_to_enum( blend.alpha_equation )
                        );

                        m_render_state.blending.rgb_equation   = blend.rgb_equation;
                        m_render_state.blending.alpha_equation = blend.alpha_equation;
                }

                if (( m_render_state.blending.color != blend.color ))
                {
                        glBlendColor( blend.color.r, blend.color.g, blend.color.b, blend.color.a );
                        m_render_state.blending.color = blend.color;
                }
        }
}


void gl_context::apply_culling( const culling& cull )
{
        if ( m_render_state.culling.enabled != cull.enabled )
        {
                enable( GL_CULL_FACE, cull.enabled );
                m_render_state.culling.enabled = cull.enabled;
        }

        if ( cull.enabled )
        {
                if ( m_render_state.culling.face != cull.face )
                {
                        glCullFace( culling_face_type_to_enum(cull.face) );
                        m_render_state.culling.face = cull.face;
                }

                if ( m_render_state.culling.order != cull.order )
                {
                        glFrontFace( culling_order_type_to_enum( cull.order ) );
                        m_render_state.culling.order = cull.order;
                }
        }
}


void gl_context::force_apply_render_state( const render_state& state )
{
        enable( GL_CULL_FACE, state.culling.enabled );
        glCullFace( culling_face_type_to_enum( state.culling.face ) );
        glFrontFace( culling_order_type_to_enum( state.culling.order ) );

        enable( GL_SCISSOR_TEST, state.scissor_test.enabled );
        glScissor( 
                state.scissor_test.pos.x, state.scissor_test.pos.y, 
                state.scissor_test.dim.x, state.scissor_test.dim.y 
        );

        enable( GL_STENCIL_TEST, state.stencil_test.enabled );
        force_apply_stencil_face( GL_FRONT, state.stencil_test.front_face );
        force_apply_stencil_face( GL_BACK,  state.stencil_test.back_face  );

        enable( GL_DEPTH_TEST, state.depth_test.enabled );
        glDepthFunc( depth_state_function_to_enum( state.depth_test.function ) );
        glDepthRange( state.depth_range.near, state.depth_range.far );

        enable( GL_BLEND, state.blending.enabled );
        glBlendFuncSeparate(
                blending_factor_to_enum( state.blending.src_rgb_factor ),
                blending_factor_to_enum( state.blending.dst_rgb_factor ),
                blending_factor_to_enum( state.blending.src_alpha_factor ),
                blending_factor_to_enum( state.blending.dst_alpha_factor )
        );
        glBlendEquationSeparate(
                blending_equation_to_enum( state.blending.rgb_equation ),
                blending_equation_to_enum( state.blending.alpha_equation )
        );
        glBlendColor( 
                state.blending.color.r, state.blending.color.g, 
                state.blending.color.b, state.blending.color.a 
        );

        glDepthMask( state.depth_mask );
        glColorMask( 
                state.color_mask.red, state.color_mask.green, 
                state.color_mask.blue, state.color_mask.alpha 
        );
}

void gl_context::force_apply_stencil_face( int face, const stencil_test_face& stencil )
{
        glStencilOpSeparate( face,
                stencil_operation_to_enum( stencil.op_fail ),
                stencil_operation_to_enum( stencil.op_depth_fail ),
                stencil_operation_to_enum( stencil.op_depth_pass )
        );

        glStencilFuncSeparate( face,
                stencil_function_to_enum( stencil.function ),
                stencil.ref_value,
                stencil.mask
        );
}


void gl_context::apply_render_state( const render_state& state )
{
        // apply_primitive_restart
        apply_culling( state.culling );
        // apply_program_point_size
        // apply_rasterization_mode
        apply_scissor_test( state.scissor_test );
        apply_stencil_test( state.stencil_test );
        apply_depth_test( state.depth_test );
        apply_depth_range( state.depth_range );
        apply_blending( state.blending );
        apply_color_mask( state.color_mask );
        apply_depth_mask( state.depth_mask );
}