ContextLines.cpp - This C++ code is part of a graphics rend…

/opengles/src/ContextLines.cpp

http://ftk.googlecode.com/ · C++ · 440 lines · 284 code · 109 blank · 47 comment · 40 complexity · 416a1bc44250a5058265daa014cb4ecb MD5 · raw file


// ==========================================================================
//
// ContextLines.cpp	Rendering Context Class for 3D Rendering Library
//
//					Rendering Operations for Lines
//
// --------------------------------------------------------------------------
//
// 08-12-2003	Hans-Martin Will	initial version
//
// --------------------------------------------------------------------------
//
// Copyright (c) 2004, Hans-Martin Will. All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions are 
// met:
// 
//	 *  Redistributions of source code must retain the above copyright
// 		notice, this list of conditions and the following disclaimer. 
//   *	Redistributions in binary form must reproduce the above copyright
// 		notice, this list of conditions and the following disclaimer in the 
// 		documentation and/or other materials provided with the distribution. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 
// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
// THE POSSIBILITY OF SUCH DAMAGE.
//
// ==========================================================================


#include "stdafx.h"
#include "Context.h"
#include "fixed.h"
#include "Rasterizer.h"

using namespace EGL;


void Context :: LineWidthx(GLfixed width) { 

	if (width <= 0) {
		RecordError(GL_INVALID_VALUE);
	} else {
		GetRasterizerState()->SetLineWidth(width);
	}
}


// --------------------------------------------------------------------------
// Lines
// --------------------------------------------------------------------------


void Context :: RenderLines(GLint first, GLsizei count) {

	m_Rasterizer->PrepareLine();

	while (count >= 2) {
		count -= 2;

		RasterPos pos0, pos1;
		SelectArrayElement(first++);
		CurrentValuesToRasterPos(&pos0);
		SelectArrayElement(first++);
		CurrentValuesToRasterPos(&pos1);

		RenderLine(pos0, pos1);
	}
}


void Context :: RenderLines(GLsizei count, const GLubyte * indices) {

	m_Rasterizer->PrepareLine();

	while (count >= 2) {
		count -= 2;

		RasterPos pos0, pos1;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos1);

		RenderLine(pos0, pos1);
	}
}


void Context :: RenderLines(GLsizei count, const GLushort * indices) {

	m_Rasterizer->PrepareLine();

	while (count >= 2) {
		count -= 2;

		RasterPos pos0, pos1;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos1);

		RenderLine(pos0, pos1);
	}
}


// --------------------------------------------------------------------------
// Line Strips
// --------------------------------------------------------------------------


void Context :: RenderLineStrip(GLint first, GLsizei count) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1;
		SelectArrayElement(first++);
		CurrentValuesToRasterPos(&pos0);
		--count;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
		}
	}
}


void Context :: RenderLineStrip(GLsizei count, const GLubyte * indices) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		--count;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
		}
	}
}


void Context :: RenderLineStrip(GLsizei count, const GLushort * indices) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		--count;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
		}
	}
}


// --------------------------------------------------------------------------
// Line Loops
// --------------------------------------------------------------------------


void Context :: RenderLineLoop(GLint first, GLsizei count) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1, start;
		SelectArrayElement(first++);
		CurrentValuesToRasterPos(&start);
		SelectArrayElement(first++);
		CurrentValuesToRasterPos(&pos0);
		RenderLine(start, pos0);

		count -= 2;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(first++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
			RenderLine(pos1, start);
		} else {
			RenderLine(pos0, start);
		}
	}
}


void Context :: RenderLineLoop(GLsizei count, const GLubyte * indices) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1, start;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&start);
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		RenderLine(start, pos0);

		count -= 2;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
			RenderLine(pos1, start);
		} else {
			RenderLine(pos0, start);
		}
	}
}


void Context :: RenderLineLoop(GLsizei count, const GLushort * indices) {

	if (count >= 2) {
		m_Rasterizer->PrepareLine();

		RasterPos pos0, pos1, start;
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&start);
		SelectArrayElement(*indices++);
		CurrentValuesToRasterPos(&pos0);
		RenderLine(start, pos0);

		count -= 2;

		while (count >= 2) {
			count -= 2;

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);

			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos0);
			RenderLine(pos1, pos0);
		}

		if (count >= 1) {
			SelectArrayElement(*indices++);
			CurrentValuesToRasterPos(&pos1);
			RenderLine(pos0, pos1);
			RenderLine(pos1, start);
		} else {
			RenderLine(pos0, start);
		}
	}
}


namespace {

	inline EGL_Fixed Interpolate(EGL_Fixed x0, EGL_Fixed x1, EGL_Fixed num, EGL_Fixed denom) {
		return x1 + (EGL_Fixed)((((I64)(x0-x1))*num)/denom);
	}

	inline void Interpolate(RasterPos& result, const RasterPos& dst, const RasterPos& src, EGL_Fixed num, EGL_Fixed denom) {
		result.m_ClipCoords.setX(Interpolate(dst.m_ClipCoords.x(), src.m_ClipCoords.x(), num, denom));
		result.m_ClipCoords.setY(Interpolate(dst.m_ClipCoords.y(), src.m_ClipCoords.y(), num, denom));
		result.m_ClipCoords.setZ(Interpolate(dst.m_ClipCoords.z(), src.m_ClipCoords.z(), num, denom));
		result.m_ClipCoords.setW(Interpolate(dst.m_ClipCoords.w(), src.m_ClipCoords.w(), num, denom));
		result.m_Color.r = Interpolate(dst.m_Color.r, src.m_Color.r, num, denom);
		result.m_Color.g = Interpolate(dst.m_Color.g, src.m_Color.g, num, denom);
		result.m_Color.b = Interpolate(dst.m_Color.b, src.m_Color.b, num, denom);
		result.m_Color.a = Interpolate(dst.m_Color.a, src.m_Color.a, num, denom);

		for (size_t index = 0; index < EGL_NUM_TEXTURE_UNITS; ++index) {
			result.m_TextureCoords[index].tu = Interpolate(dst.m_TextureCoords[index].tu, src.m_TextureCoords[index].tu, num, denom);
			result.m_TextureCoords[index].tv = Interpolate(dst.m_TextureCoords[index].tv, src.m_TextureCoords[index].tv, num, denom);
		}

		result.m_FogDensity = Interpolate(dst.m_FogDensity, src.m_FogDensity, num, denom);
	}

	inline bool ClipX(RasterPos*& from, RasterPos*& to, RasterPos *&tempVertices) {
#		define COORDINATE x()
#		include "LineClipper.inc"
#		undef COORDINATE
	}

	inline bool ClipY(RasterPos*& from, RasterPos*& to, RasterPos *&tempVertices) {
#		define COORDINATE y()
#		include "LineClipper.inc"
#		undef COORDINATE
	}

	inline bool ClipZ(RasterPos*& from, RasterPos*& to, RasterPos *&tempVertices) {
#		define COORDINATE z()
#		include "LineClipper.inc"
#		undef COORDINATE
	}

	inline bool ClipUser(const Vec4D& plane, RasterPos*& from, RasterPos*& to, RasterPos *&tempVertices) {

		EGL_Fixed f = from->m_EyeCoords * plane;
		EGL_Fixed t = to->m_EyeCoords * plane;

		if (f < 0) {
			if (t < 0) {
				return false;
			}

			Interpolate(*tempVertices, *from, *to, t, t - f);
			from = tempVertices++;

			return true;

		} else if (t < 0) {

			Interpolate(*tempVertices, *to, *from, f, f - t);
			to = tempVertices++;

			return true;

		} else {
			// no clipping
			return true;
		}
	}
}


void Context :: RenderLine(RasterPos& from, RasterPos& to) {

	RasterPos * tempVertices = m_Temporary;
	RasterPos * pFrom = &from;
	RasterPos * pTo = &to;

	if (m_ClipPlaneEnabled) {
		for (size_t index = 0, mask = 1; index < NUM_CLIP_PLANES; ++index, mask <<= 1) {
			if (m_ClipPlaneEnabled & mask) {
				if (!ClipUser(m_ClipPlanes[index], pFrom, pTo, tempVertices)) {
					return;
				}
			}
		}
	}

	if (ClipX(pFrom, pTo, tempVertices) &&
		ClipY(pFrom, pTo, tempVertices) &&
		ClipZ(pFrom, pTo, tempVertices)) {

		ClipCoordsToWindowCoords(*pFrom);
		ClipCoordsToWindowCoords(*pTo);

		if (m_RasterizerState.GetShadeModel() == RasterizerState::ShadeModelSmooth) {
			pFrom->m_Color = pFrom->m_FrontColor;
		} else {
			pFrom->m_Color = pTo->m_FrontColor;
		}

		pTo->m_Color = pTo->m_FrontColor;
		m_Rasterizer->RasterLine(*pFrom, *pTo);
	}
}

Summary ✨

This C++ code is part of a graphics rendering engine, specifically responsible for drawing lines on the screen. It handles clipping (removing parts outside the visible area), color interpolation, and texture coordinate transformation. The RenderLine function takes two points as input and renders them to the screen, applying any necessary transformations and effects before doing so.

Alerts (4)

Complexity hotspot; lines 412 to 415 (total complexity: 4)
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