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OpenGLState.h
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OpenGLState.h
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#pragma once
#include "igl.h"
#include "ishaders.h"
#include "ishaderlayer.h"
#include "debugging/gl.h"
#include "render/Colour4.h"
// Full declaration in iglprogram.h
class GLProgram;
namespace render
{
/**
* \brief
* Data structure encapsulating various parameters of the OpenGL state machine,
* as well as parameters used internally by Radiant.
*
* The OpenGLState class is used to keep track of OpenGL state parameters used
* by the renderer, in order to avoid using slow glGet() calls or repeatedly
* changing states to the same value. Each shader pass keeps an OpenGLState
* member which stores the state values it wishes to use, and these values are
* selectively applied to a single "current" OpenGLState object maintained by
* the render system.
*/
class OpenGLState
{
public:
/// Enum of possible sort positions
enum SortPosition
{
SORT_FIRST = -64,
SORT_ZFILL = 0, // used by depth buffer fill passes
SORT_INTERACTION = 2, // used by the DBS pass
SORT_FULLBRIGHT = 1025, // used by non-translucent editor passes
SORT_TRANSLUCENT = 1026, // used by blend-type editor passes
SORT_OVERLAY_FIRST = 1028, // used by decals
SORT_OVERLAY_SECOND = 1029, // used by merge actions
SORT_OVERLAY_THIRD = 1030, // used by merge actions
SORT_OVERLAY_ONE_BEFORE_LAST = 2046, // used by merge actions
SORT_OVERLAY_LAST = 2047,
SORT_HIGHLIGHT = 2048, // used by the (red) selection system overlay
SORT_POINT_FIRST = 2049, // used by POINT renderers
SORT_POINT_LAST = 3071,
SORT_GUI0 = 3072, // used by selection system controls, pivots (visible)
SORT_GUI1 = 3073, // used by selection system controls, pivots (obscured)
SORT_LAST = 4096,
};
private:
// The 4 colour components, only for use in OpenGLStates that do not have
// any shader stages attached, otherwise pull the colour from there.
Colour4 _colour;
// Colour inversion flag
IShaderLayer::VertexColourMode _vertexColourMode;
// Set of RENDER_XXX flags
unsigned _renderFlags;
// GL depth function
GLenum _glDepthFunc;
// Sort position
SortPosition _sortPos;
std::string _name;
public:
const std::string& getName() const
{
return _name;
}
void setName(const std::string& name)
{
_name = name;
}
/// Return the glColor for this state
const Colour4& getColour() const
{
assert(_colour.isValid());
return _colour;
}
/// Set the glColor for this state, from a Vector4
void setColour(const Colour4& col)
{
assert(col.isValid());
_colour = col;
}
/// Set the glColor for this state, from individual components
void setColour(float r, float g, float b, float a)
{
setColour(Colour4(r, g, b, a));
}
IShaderLayer::VertexColourMode getVertexColourMode() const
{
return _vertexColourMode;
}
void setVertexColourMode(IShaderLayer::VertexColourMode mode)
{
_vertexColourMode = mode;
}
/// \name Render flag operations
///@{
/// Set all render flags for this state
void setRenderFlags(unsigned newFlags) { _renderFlags = newFlags; }
/// Set a single render flag on this state
void setRenderFlag(unsigned flag)
{
setRenderFlags(_renderFlags | flag);
}
/// Clear a single render flag on this state
void clearRenderFlag(unsigned flag)
{
setRenderFlags(_renderFlags & ~flag);
}
/// Test the value of a single render flag
bool testRenderFlag(unsigned flag) const
{
return (_renderFlags & flag) > 0;
}
/// Return the render flags for this state
unsigned getRenderFlags() const { return _renderFlags; }
///@}
/// Return the depth function
GLenum getDepthFunc() const { return _glDepthFunc; }
/// Set the depth function
void setDepthFunc(GLenum func) { _glDepthFunc = func; }
/// Return the sort position
SortPosition getSortPosition() const { return _sortPos; }
/// Set the sort position
void setSortPosition(SortPosition pos) { _sortPos = pos; }
/**
* \brief
* Polygon offset.
*/
float polygonOffset;
/**
* \brief
* GL texture numbers to be bound to texture units.
*
* \{
*/
GLuint texture0; // diffuse
GLuint texture1; // bump
GLuint texture2; // specular
GLuint texture3; // light texture
GLuint texture4; // light falloff
GLuint texture5; // shadow map
/**
* \}
*/
/**
* Each open GL State refers to one or more shader stages,
* which hold the actual values of many parameters, some of them
* time-dependent or depending on entity parameters.
*/
IShaderLayer::Ptr stage0;
IShaderLayer::Ptr stage1;
IShaderLayer::Ptr stage2;
IShaderLayer::Ptr stage3;
IShaderLayer::Ptr stage4;
/**
* \brief
* Source blend mode.
*/
GLenum m_blend_src;
/**
* \brief
* Destination blend mode
*/
GLenum m_blend_dst;
// Alpha test function
GLenum alphaFunc;
// Alpha test threshold
GLfloat alphaThreshold;
GLfloat m_linewidth;
GLfloat m_pointsize;
GLint m_linestipple_factor;
GLushort m_linestipple_pattern;
/**
* \brief
* GL program or shader object.
*/
GLProgram* glProgram;
/**
* \brief
* The cube-map texgen mode for rendering.
*/
IShaderLayer::CubeMapMode cubeMapMode;
/// Default constructor
OpenGLState()
: _colour(Colour4::WHITE()),
_vertexColourMode(IShaderLayer::VERTEX_COLOUR_NONE),
_renderFlags(0),
_glDepthFunc(GL_LESS),
_sortPos(SORT_FIRST),
polygonOffset(0.0f),
texture0(0),
texture1(0),
texture2(0),
texture3(0),
texture4(0),
texture5(0),
m_blend_src(GL_SRC_ALPHA),
m_blend_dst(GL_ONE_MINUS_SRC_ALPHA),
alphaFunc(GL_ALWAYS),
alphaThreshold(0),
m_linewidth(1),
m_pointsize(1),
m_linestipple_factor(1),
m_linestipple_pattern(0xAAAA),
glProgram(nullptr),
cubeMapMode(IShaderLayer::CUBE_MAP_NONE)
{ }
// Determines the difference between this state and the target (current) state.
// Issues the state calls required by this state and updates the target state
// to reflect the changes.
// The given globalStateMask controls which state changes are allowed in the first place.
void applyTo(OpenGLState& current, unsigned int globalStateMask)
{
// Apply the global state mask to our own desired render flags to determine
// the final set of flags that allow and require changing
const unsigned requiredState = _renderFlags & globalStateMask;
// Construct a mask containing all the flags that will be changing between
// the current state and the required state. This avoids performing
// unnecessary GL calls to set the state to its existing value.
const unsigned changingBitsMask = requiredState ^ current.getRenderFlags();
// Set the GLProgram if required
if (requiredState & RENDER_PROGRAM)
{
activateShaderProgram(current);
}
else
{
deactivateShaderProgram(current);
}
// State changes. Only perform these if changingBitsMask > 0, since if there are
// no changes required we don't want a whole load of unnecessary bit operations.
if (changingBitsMask != 0)
{
if (changingBitsMask & requiredState & RENDER_FILL)
{
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_FILL)
{
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
debug::assertNoGlErrors();
}
setState(requiredState, changingBitsMask, RENDER_OFFSETLINE, GL_POLYGON_OFFSET_LINE);
if (changingBitsMask & requiredState & RENDER_LIGHTING)
{
glEnable(GL_LIGHTING);
glEnable(GL_COLOR_MATERIAL);
glEnableClientState(GL_NORMAL_ARRAY);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_LIGHTING)
{
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);
glDisableClientState(GL_NORMAL_ARRAY);
debug::assertNoGlErrors();
}
// RENDER_TEXTURE_CUBEMAP
if (changingBitsMask & requiredState & RENDER_TEXTURE_CUBEMAP)
{
setTexture0();
glEnable(GL_TEXTURE_CUBE_MAP);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_TEXTURE_CUBEMAP)
{
setTexture0();
glDisable(GL_TEXTURE_CUBE_MAP);
glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
debug::assertNoGlErrors();
}
// RENDER_TEXTURE_2D
if (changingBitsMask & requiredState & RENDER_TEXTURE_2D)
{
setTexture0();
glEnable(GL_TEXTURE_2D);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_TEXTURE_2D)
{
setTexture0();
glDisable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, 0);
debug::assertNoGlErrors();
}
// RENDER_BLEND
if (changingBitsMask & requiredState & RENDER_BLEND)
{
glEnable(GL_BLEND);
setTexture0();
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_BLEND)
{
glDisable(GL_BLEND);
setTexture0();
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
debug::assertNoGlErrors();
}
setState(requiredState, changingBitsMask, RENDER_CULLFACE, GL_CULL_FACE);
if (changingBitsMask & requiredState & RENDER_SMOOTH)
{
glShadeModel(GL_SMOOTH);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_SMOOTH)
{
glShadeModel(GL_FLAT);
debug::assertNoGlErrors();
}
setState(requiredState, changingBitsMask, RENDER_SCALED, GL_NORMALIZE); // not GL_RESCALE_NORMAL
setState(requiredState, changingBitsMask, RENDER_DEPTHTEST, GL_DEPTH_TEST);
if (changingBitsMask & requiredState & RENDER_DEPTHWRITE)
{
glDepthMask(GL_TRUE);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_DEPTHWRITE)
{
glDepthMask(GL_FALSE);
debug::assertNoGlErrors();
}
// Disable colour buffer writes if required
if (changingBitsMask & requiredState & RENDER_MASKCOLOUR)
{
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
debug::assertNoGlErrors();
}
else if (changingBitsMask & ~requiredState & RENDER_MASKCOLOUR)
{
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
debug::assertNoGlErrors();
}
setState(requiredState, changingBitsMask, RENDER_ALPHATEST, GL_ALPHA_TEST);
// Set GL states corresponding to RENDER_ flags
setState(requiredState, changingBitsMask, RENDER_LINESTIPPLE, GL_LINE_STIPPLE);
setState(requiredState, changingBitsMask, RENDER_POLYGONSTIPPLE, GL_POLYGON_STIPPLE);
} // end of changingBitsMask-dependent changes
// Set depth function
if (requiredState & RENDER_DEPTHTEST && getDepthFunc() != current.getDepthFunc())
{
glDepthFunc(getDepthFunc());
debug::assertNoGlErrors();
current.setDepthFunc(getDepthFunc());
}
if (requiredState & RENDER_LINESTIPPLE
&& (m_linestipple_factor != current.m_linestipple_factor
|| m_linestipple_pattern != current.m_linestipple_pattern))
{
glLineStipple(m_linestipple_factor, m_linestipple_pattern);
debug::assertNoGlErrors();
current.m_linestipple_factor = m_linestipple_factor;
current.m_linestipple_pattern = m_linestipple_pattern;
}
// Set up the alpha test parameters
if (requiredState & RENDER_ALPHATEST &&
(alphaFunc != current.alphaFunc || alphaThreshold != current.alphaThreshold))
{
// Set alpha function in GL
glAlphaFunc(alphaFunc, alphaThreshold);
debug::assertNoGlErrors();
// Store state values
current.alphaFunc = alphaFunc;
current.alphaThreshold = alphaThreshold;
}
// Apply polygon offset
if (polygonOffset != current.polygonOffset)
{
current.polygonOffset = polygonOffset;
if (current.polygonOffset > 0.0f)
{
glEnable(GL_POLYGON_OFFSET_FILL);
glPolygonOffset(-1, -1 * polygonOffset);
}
else
{
glDisable(GL_POLYGON_OFFSET_FILL);
}
}
// Apply the GL textures
applyAllTextures(current, requiredState);
// Set the GL colour. Do this unconditionally, since setting glColor is
// cheap and it avoids problems with leaked colour states.
if (stage0)
{
setColour(stage0->getColour());
}
glColor4fv(getColour());
current.setColour(getColour());
debug::assertNoGlErrors();
if (requiredState & RENDER_BLEND
&& (m_blend_src != current.m_blend_src || m_blend_dst != current.m_blend_dst))
{
glBlendFunc(m_blend_src, m_blend_dst);
debug::assertNoGlErrors();
current.m_blend_src = m_blend_src;
current.m_blend_dst = m_blend_dst;
}
if (!(requiredState & RENDER_FILL) && m_linewidth != current.m_linewidth)
{
glLineWidth(m_linewidth);
debug::assertNoGlErrors();
current.m_linewidth = m_linewidth;
}
if (!(requiredState & RENDER_FILL) && m_pointsize != current.m_pointsize)
{
glPointSize(m_pointsize);
debug::assertNoGlErrors();
current.m_pointsize = m_pointsize;
}
// Propagate the invert vertex colour flag
if (requiredState & RENDER_VERTEX_COLOUR)
{
current.setVertexColourMode(getVertexColourMode());
}
else
{
current.setVertexColourMode(IShaderLayer::VERTEX_COLOUR_NONE);
}
current.setRenderFlags(requiredState);
debug::assertNoGlErrors();
}
// Bind the given texture to the texture unit, if it is different from the
// current state, then set the current state to the new texture.
static void SetTextureState(GLuint& current, const GLuint texture, GLenum textureUnit, GLenum textureMode)
{
if (texture == current) return;
glActiveTexture(textureUnit);
glClientActiveTexture(textureUnit);
glBindTexture(textureMode, texture);
debug::assertNoGlErrors();
current = texture;
}
private:
void setupTextureMatrix(GLenum textureUnit, const IShaderLayer::Ptr& stage)
{
// Set the texture matrix for the given unit
glActiveTexture(textureUnit);
glClientActiveTexture(textureUnit);
if (!stage)
{
glLoadIdentity();
return;
}
auto tex = stage->getTextureTransform();
glLoadMatrixd(tex);
}
void setTextureState(GLuint& current, const GLuint texture, GLenum textureMode)
{
if (texture == current) return;
glBindTexture(textureMode, texture);
debug::assertNoGlErrors();
current = texture;
}
// Apply all textures to texture units
void applyAllTextures(OpenGLState& current, unsigned requiredState)
{
// Set the texture dimensionality from render flags. There is only a global
// mode for all textures, we can't have texture1 as 2D and texture2 as
// CUBE_MAP for example.
GLenum textureMode = 0;
if (requiredState & RENDER_TEXTURE_CUBEMAP) // cube map has priority
{
textureMode = GL_TEXTURE_CUBE_MAP;
}
else if (requiredState & RENDER_TEXTURE_2D)
{
textureMode = GL_TEXTURE_2D;
}
// Apply our texture numbers to the current state
if (textureMode != 0) // only if one of the RENDER_TEXTURE options
{
glMatrixMode(GL_TEXTURE);
if (GLEW_VERSION_1_3)
{
SetTextureState(current.texture0, texture0, GL_TEXTURE0, textureMode);
setupTextureMatrix(GL_TEXTURE0, stage0);
SetTextureState(current.texture1, texture1, GL_TEXTURE1, textureMode);
setupTextureMatrix(GL_TEXTURE1, stage1);
SetTextureState(current.texture2, texture2, GL_TEXTURE2, textureMode);
setupTextureMatrix(GL_TEXTURE2, stage2);
SetTextureState(current.texture3, texture2, GL_TEXTURE2, textureMode);
SetTextureState(current.texture4, texture2, GL_TEXTURE2, textureMode);
glActiveTexture(GL_TEXTURE0);
glClientActiveTexture(GL_TEXTURE0);
}
else
{
setTextureState(current.texture0, texture0, textureMode);
setupTextureMatrix(GL_TEXTURE0, stage0);
}
glMatrixMode(GL_MODELVIEW);
}
}
void setTexture0()
{
glActiveTexture(GL_TEXTURE0);
glClientActiveTexture(GL_TEXTURE0);
}
// Utility function to toggle an OpenGL state flag
void setState(unsigned int state, unsigned int delta, unsigned int flag, GLenum glflag)
{
if (delta & state & flag)
{
glEnable(glflag);
debug::assertNoGlErrors();
}
else if (delta & ~state & flag)
{
glDisable(glflag);
debug::assertNoGlErrors();
}
}
void activateShaderProgram(OpenGLState& current)
{
if (current.glProgram == glProgram)
{
// nothing to do
return;
}
// Deactivate the previous program first
deactivateShaderProgram(current);
if (glProgram != nullptr)
{
current.glProgram = glProgram;
current.glProgram->enable();
}
}
void deactivateShaderProgram(OpenGLState& current)
{
if (current.glProgram == nullptr) return;
current.glProgram->disable();
current.glProgram = nullptr;
}
};
}