bloom shader

This commit is contained in:
Eduardo Bart 2011-12-07 21:43:12 -02:00
parent b5cf4ad2c4
commit 5ec386b35f
10 changed files with 136 additions and 126 deletions

View File

@ -1,5 +1,40 @@
uniform sampler2D texture; uniform sampler2D texture;
varying vec2 textureCoords; varying vec2 textureCoords;
void main()
{
vec4 sum = vec4(0);
vec2 texcoord = textureCoords;
int j;
int i;
for( i= -4 ;i < 4; i++)
{
for (j = -3; j < 3; j++)
{
sum += texture2D(texture, texcoord + vec2(j, i)*0.004) * 0.25;
}
}
if (texture2D(texture, texcoord).r < 0.3)
{
gl_FragColor = sum*sum*0.012 + texture2D(texture, texcoord);
}
else
{
if (texture2D(texture, texcoord).r < 0.5)
{
gl_FragColor = sum*sum*0.009 + texture2D(texture, texcoord);
}
else
{
gl_FragColor = sum*sum*0.0075 + texture2D(texture, texcoord);
}
}
}
/*
uniform sampler2D texture;
varying vec2 textureCoords;
uniform vec4 color; uniform vec4 color;
uniform float opacity; uniform float opacity;
@ -35,7 +70,7 @@ void main (void)
vec2 uv = textureCoords.st; vec2 uv = textureCoords.st;
gl_FragColor = PostFX(texture, uv, ticks) * opacity; gl_FragColor = PostFX(texture, uv, ticks) * opacity;
} }
*/
/* /*
uniform float opacity; uniform float opacity;
vec4 calculatePixel(); vec4 calculatePixel();

View File

@ -27,7 +27,7 @@ void CoordsBuffer::clear()
m_destRects.reset(); m_destRects.reset();
m_srcRects.reset(); m_srcRects.reset();
m_textureCoords.clear(); m_textureCoords.clear();
m_vertexCoords.clear(); m_vertices.clear();
m_updateCache = true; m_updateCache = true;
} }
@ -97,11 +97,11 @@ void CoordsBuffer::cacheVertexArrays()
int numDestRects = m_destRects.size(); int numDestRects = m_destRects.size();
int numSrcRects = m_srcRects.size(); int numSrcRects = m_srcRects.size();
m_vertexCoords.clear(); m_vertices.clear();
m_textureCoords.clear(); m_textureCoords.clear();
for(int i=0;i<numDestRects;++i) { for(int i=0;i<numDestRects;++i) {
m_vertexCoords.addRect(m_destRects[i]); m_vertices.addRect(m_destRects[i]);
if(numSrcRects == numDestRects) if(numSrcRects == numDestRects)
m_textureCoords.addRect(m_srcRects[i]); m_textureCoords.addRect(m_srcRects[i]);
} }

View File

@ -40,14 +40,15 @@ public:
void cacheVertexArrays(); void cacheVertexArrays();
GLfloat *getVertexCoords() const { return m_vertexCoords.vertexArray(); } GLfloat *getVertices() const { return m_vertices.vertices(); }
GLfloat *getTextureCoords() const { return m_textureCoords.vertexArray(); } GLfloat *getTextureCoords() const { return m_textureCoords.vertices(); }
int getVertexCount() const { return m_vertexCoords.vertexCount(); } int getVertexCount() const { return m_vertices.vertexCount(); }
int getTextureCoordsCount() const { return m_textureCoords.vertexCount(); }
private: private:
DataBuffer<Rect> m_destRects; DataBuffer<Rect> m_destRects;
DataBuffer<Rect> m_srcRects; DataBuffer<Rect> m_srcRects;
VertexArray m_vertexCoords; VertexArray m_vertices;
VertexArray m_textureCoords; VertexArray m_textureCoords;
Boolean<true> m_updateCache; Boolean<true> m_updateCache;
}; };

View File

@ -36,30 +36,15 @@ void Painter::init()
setOpacity(255); setOpacity(255);
setCompositionMode(CompositionMode_SourceOver); setCompositionMode(CompositionMode_SourceOver);
PainterShaderProgramPtr program = PainterShaderProgramPtr(new PainterShaderProgram); m_drawTexturedProgram = PainterShaderProgramPtr(new PainterShaderProgram);
program->addShaderFromSourceCode(Shader::Vertex, glslMainWithTexCoordsVertexShader + glslPositionOnlyVertexShader); m_drawTexturedProgram->addShaderFromSourceCode(Shader::Vertex, glslMainWithTexCoordsVertexShader + glslPositionOnlyVertexShader);
program->addShaderFromSourceCode(Shader::Fragment, glslMainFragmentShader + glslTextureSrcFragmentShader); m_drawTexturedProgram->addShaderFromSourceCode(Shader::Fragment, glslMainFragmentShader + glslTextureSrcFragmentShader);
program->bindAttributeLocation(VERTEX_COORDS_ATTR, "vertexCoord"); assert(m_drawTexturedProgram->link());
program->bindAttributeLocation(TEXTURE_COORDS_ATTR, "textureCoord");
assert(program->link());
program->bindUniformLocation(PainterShaderProgram::PROJECTION_MATRIX_UNIFORM, "projectionMatrix");
program->bindUniformLocation(PainterShaderProgram::TEXTURE_TRANSFORM_MATRIX_UNIFORM, "textureTransformMatrix");
program->bindUniformLocation(PainterShaderProgram::COLOR_UNIFORM, "color");
program->bindUniformLocation(PainterShaderProgram::OPACITY_UNIFORM, "opacity");
program->bindUniformLocation(PainterShaderProgram::TEXTURE_UNIFORM, "texture");
program->bindUniformLocation(PainterShaderProgram::TICKS_UNIFORM, "ticks");
m_drawTexturedProgram = program;
program = PainterShaderProgramPtr(new PainterShaderProgram); m_drawSolidColorProgram = PainterShaderProgramPtr(new PainterShaderProgram);
program->addShaderFromSourceCode(Shader::Vertex, glslMainVertexShader + glslPositionOnlyVertexShader); m_drawSolidColorProgram->addShaderFromSourceCode(Shader::Vertex, glslMainVertexShader + glslPositionOnlyVertexShader);
program->addShaderFromSourceCode(Shader::Fragment, glslMainFragmentShader + glslSolidColorFragmentShader); m_drawSolidColorProgram->addShaderFromSourceCode(Shader::Fragment, glslMainFragmentShader + glslSolidColorFragmentShader);
program->bindAttributeLocation(VERTEX_COORDS_ATTR, "vertexCoord"); assert(m_drawSolidColorProgram->link());
assert(program->link());
program->bindUniformLocation(PainterShaderProgram::PROJECTION_MATRIX_UNIFORM, "projectionMatrix");
program->bindUniformLocation(PainterShaderProgram::COLOR_UNIFORM, "color");
program->bindUniformLocation(PainterShaderProgram::OPACITY_UNIFORM, "opacity");
program->bindUniformLocation(PainterShaderProgram::TICKS_UNIFORM, "ticks");
m_drawSolidColorProgram = program;
} }
void Painter::terminate() void Painter::terminate()
@ -97,38 +82,23 @@ void Painter::updateProjectionMatrix(const Size& viewportSize, bool inverseYAxis
} }
} }
void Painter::drawCoords(CoordsBuffer& coordsBuffer) void Painter::drawProgram(const PainterShaderProgramPtr& program, CoordsBuffer& coordsBuffer, PainterShaderProgram::DrawMode drawMode)
{ {
coordsBuffer.cacheVertexArrays(); coordsBuffer.cacheVertexArrays();
if(coordsBuffer.getVertexCount() == 0)
if(coordsBuffer.getVertexCount() < 3)
return; return;
m_drawSolidColorProgram->prepareForDraw(); program->setProjectionMatrix(m_projectionMatrix);
m_drawSolidColorProgram->setProjectionMatrix(m_projectionMatrix); program->setOpacity(m_currentOpacity);
m_drawSolidColorProgram->setOpacity(m_currentOpacity); program->setColor(m_currentColor);
m_drawSolidColorProgram->setColor(m_currentColor); program->draw(coordsBuffer, drawMode);
m_drawSolidColorProgram->setVertexCoords(coordsBuffer.getVertexCoords());
m_drawSolidColorProgram->drawTriangles(coordsBuffer.getVertexCount());
m_drawSolidColorProgram->releaseFromDraw();
} }
void Painter::drawTextureCoords(CoordsBuffer& coordsBuffer, const TexturePtr& texture) void Painter::drawTextureCoords(CoordsBuffer& coordsBuffer, const TexturePtr& texture)
{ {
coordsBuffer.cacheVertexArrays(); PainterShaderProgramPtr program = m_customProgram ? m_customProgram : m_drawTexturedProgram;
program->setTexture(texture);
if(coordsBuffer.getVertexCount() < 3) drawProgram(program, coordsBuffer);
return;
m_drawTexturedProgram->prepareForDraw();
m_drawTexturedProgram->setProjectionMatrix(m_projectionMatrix);
m_drawTexturedProgram->setOpacity(m_currentOpacity);
m_drawTexturedProgram->setColor(m_currentColor);
m_drawTexturedProgram->setTexture(texture);
m_drawTexturedProgram->setVertexCoords(coordsBuffer.getVertexCoords());
m_drawTexturedProgram->setTextureCoords(coordsBuffer.getTextureCoords());
m_drawTexturedProgram->drawTriangles(coordsBuffer.getVertexCount());
m_drawTexturedProgram->releaseFromDraw();
} }
void Painter::drawTexturedRect(const Rect& dest, const TexturePtr& texture) void Painter::drawTexturedRect(const Rect& dest, const TexturePtr& texture)
@ -163,7 +133,7 @@ void Painter::drawFilledRect(const Rect& dest)
m_coordsBuffer.clear(); m_coordsBuffer.clear();
m_coordsBuffer.addRect(dest); m_coordsBuffer.addRect(dest);
drawCoords(m_coordsBuffer); drawProgram(m_customProgram ? m_customProgram : m_drawSolidColorProgram, m_coordsBuffer);
} }
void Painter::drawBoundingRect(const Rect& dest, int innerLineWidth) void Painter::drawBoundingRect(const Rect& dest, int innerLineWidth)
@ -173,7 +143,12 @@ void Painter::drawBoundingRect(const Rect& dest, int innerLineWidth)
m_coordsBuffer.clear(); m_coordsBuffer.clear();
m_coordsBuffer.addBoudingRect(dest, innerLineWidth); m_coordsBuffer.addBoudingRect(dest, innerLineWidth);
drawCoords(m_coordsBuffer); drawProgram(m_customProgram ? m_customProgram : m_drawSolidColorProgram, m_coordsBuffer);
}
void Painter::setCustomProgram(PainterShaderProgramPtr program)
{
m_customProgram = program;
} }
void Painter::setCompositionMode(Painter::CompositionMode compositionMode) void Painter::setCompositionMode(Painter::CompositionMode compositionMode)

View File

@ -26,6 +26,7 @@
#include "declarations.h" #include "declarations.h"
#include <framework/util/databuffer.h> #include <framework/util/databuffer.h>
#include "coordsbuffer.h" #include "coordsbuffer.h"
#include "paintershaderprogram.h"
class Painter class Painter
{ {
@ -40,9 +41,8 @@ public:
void updateProjectionMatrix(const Size& viewportSize, bool inverseYAxis = false); void updateProjectionMatrix(const Size& viewportSize, bool inverseYAxis = false);
void drawCoords(CoordsBuffer& coordsBuffer); void drawProgram(const PainterShaderProgramPtr& program, CoordsBuffer& coordsBuffer, PainterShaderProgram::DrawMode drawMode = PainterShaderProgram::Triangles);
void drawTextureCoords(CoordsBuffer& coordsBuffer, const TexturePtr& texture); void drawTextureCoords(CoordsBuffer& coordsBuffer, const TexturePtr& texture);
void drawTexturedRect(const Rect& dest, const TexturePtr& texture); void drawTexturedRect(const Rect& dest, const TexturePtr& texture);
void drawTexturedRect(const Rect& dest, const TexturePtr& texture, const Rect& src); void drawTexturedRect(const Rect& dest, const TexturePtr& texture, const Rect& src);
void drawRepeatedTexturedRect(const Rect& dest, const TexturePtr& texture, const Rect& src); void drawRepeatedTexturedRect(const Rect& dest, const TexturePtr& texture, const Rect& src);
@ -55,6 +55,8 @@ public:
void setOpacity(int opacity) { m_currentOpacity = opacity / 255.0f; } void setOpacity(int opacity) { m_currentOpacity = opacity / 255.0f; }
int getOpacity() { return m_currentOpacity * 255.0f; } int getOpacity() { return m_currentOpacity * 255.0f; }
void setCustomProgram(PainterShaderProgramPtr program);
void releaseCustomProgram() { m_customProgram = nullptr; }
void setCompositionMode(CompositionMode compositionMode); void setCompositionMode(CompositionMode compositionMode);
GLfloat *getProjectionMatrix() { return (GLfloat*)m_projectionMatrix; } GLfloat *getProjectionMatrix() { return (GLfloat*)m_projectionMatrix; }
@ -62,6 +64,7 @@ public:
private: private:
PainterShaderProgramPtr m_drawTexturedProgram; PainterShaderProgramPtr m_drawTexturedProgram;
PainterShaderProgramPtr m_drawSolidColorProgram; PainterShaderProgramPtr m_drawSolidColorProgram;
PainterShaderProgramPtr m_customProgram;
GLfloat m_projectionMatrix[3][3]; GLfloat m_projectionMatrix[3][3];
Color m_currentColor; Color m_currentColor;
GLfloat m_currentOpacity; GLfloat m_currentOpacity;

View File

@ -26,13 +26,31 @@
#include "texturemanager.h" #include "texturemanager.h"
#include <framework/core/clock.h> #include <framework/core/clock.h>
bool PainterShaderProgram::link()
{
bindAttributeLocation(VERTEX_COORDS_ATTR, "vertexCoord");
bindAttributeLocation(TEXTURE_COORDS_ATTR, "textureCoord");
if(ShaderProgram::link()) {
bindUniformLocation(PROJECTION_MATRIX_UNIFORM, "projectionMatrix");
bindUniformLocation(TEXTURE_TRANSFORM_MATRIX_UNIFORM, "textureTransformMatrix");
bindUniformLocation(COLOR_UNIFORM, "color");
bindUniformLocation(OPACITY_UNIFORM, "opacity");
bindUniformLocation(TEXTURE_UNIFORM, "texture");
bindUniformLocation(TICKS_UNIFORM, "ticks");
return true;
}
return false;
}
void PainterShaderProgram::setProjectionMatrix(float projectionMatrix[3][3]) void PainterShaderProgram::setProjectionMatrix(float projectionMatrix[3][3])
{ {
bind();
setUniformValue(PROJECTION_MATRIX_UNIFORM, projectionMatrix, true); setUniformValue(PROJECTION_MATRIX_UNIFORM, projectionMatrix, true);
} }
void PainterShaderProgram::setColor(const Color& color) void PainterShaderProgram::setColor(const Color& color)
{ {
bind();
setUniformValue(COLOR_UNIFORM, setUniformValue(COLOR_UNIFORM,
color.r() / 255.0f, color.r() / 255.0f,
color.g() / 255.0f, color.g() / 255.0f,
@ -42,11 +60,15 @@ void PainterShaderProgram::setColor(const Color& color)
void PainterShaderProgram::setOpacity(GLfloat opacity) void PainterShaderProgram::setOpacity(GLfloat opacity)
{ {
bind();
setUniformValue(OPACITY_UNIFORM, opacity); setUniformValue(OPACITY_UNIFORM, opacity);
} }
void PainterShaderProgram::setTexture(const TexturePtr& texture) void PainterShaderProgram::setTexture(const TexturePtr& texture)
{ {
if(!texture)
return;
float w = texture->getGlSize().width(); float w = texture->getGlSize().width();
float h = texture->getGlSize().height(); float h = texture->getGlSize().height();
@ -55,52 +77,45 @@ void PainterShaderProgram::setTexture(const TexturePtr& texture)
{ 0.0f, 1.0f/h } { 0.0f, 1.0f/h }
}; };
bind();
glActiveTexture(GL_TEXTURE0); glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture->getId()); glBindTexture(GL_TEXTURE_2D, texture->getId());
setUniformValue(TEXTURE_UNIFORM, 0); setUniformValue(TEXTURE_UNIFORM, 0);
setUniformValue(TEXTURE_TRANSFORM_MATRIX_UNIFORM, textureTransformMatrix, true); setUniformValue(TEXTURE_TRANSFORM_MATRIX_UNIFORM, textureTransformMatrix, true);
} }
void PainterShaderProgram::setVertexCoords(const GLfloat *vertices) void PainterShaderProgram::draw(const CoordsBuffer& coordsBuffer, DrawMode drawMode)
{
enableAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR);
setAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR, vertices, 2);
}
void PainterShaderProgram::setTextureCoords(const GLfloat *textureCoords)
{
enableAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR);
setAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR, textureCoords, 2);
m_mustDisableTexCoordsArray = true;
}
void PainterShaderProgram::prepareForDraw()
{ {
assert(bind()); assert(bind());
setUniformValue(TICKS_UNIFORM, (GLfloat)g_clock.ticks()); setUniformValue(TICKS_UNIFORM, (GLfloat)g_clock.ticks());
int numVertices = coordsBuffer.getVertexCount();
if(numVertices == 0)
return;
bool mustDisableVertexArray = false;
if(coordsBuffer.getVertexCount() > 0) {
enableAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR);
setAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR, coordsBuffer.getVertices(), 2);
mustDisableVertexArray = true;
} }
void PainterShaderProgram::drawTriangleStrip(int numVertices) bool mustDisableTexCoordsArray = false;
{ if(coordsBuffer.getTextureCoords() > 0) {
glDrawArrays(GL_TRIANGLE_STRIP, 0, numVertices); enableAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR);
setAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR, coordsBuffer.getTextureCoords(), 2);
mustDisableTexCoordsArray = true;
} }
void PainterShaderProgram::drawTriangles(int numVertices) glDrawArrays(drawMode, 0, numVertices);
{
glDrawArrays(GL_TRIANGLES, 0, numVertices);
}
void PainterShaderProgram::releaseFromDraw() if(mustDisableVertexArray)
{
if(m_mustDisableTexCoordsArray) {
disableAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR);
m_mustDisableTexCoordsArray = false;
}
if(m_mustDisableVertexArray) {
disableAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR); disableAttributeArray(PainterShaderProgram::VERTEX_COORDS_ATTR);
m_mustDisableVertexArray = false;
} if(mustDisableTexCoordsArray)
disableAttributeArray(PainterShaderProgram::TEXTURE_COORDS_ATTR);
//release(); //release();
} }

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@ -24,10 +24,10 @@
#define PAINTERSHADER_H #define PAINTERSHADER_H
#include "shaderprogram.h" #include "shaderprogram.h"
#include "coordsbuffer.h"
class PainterShaderProgram : public ShaderProgram class PainterShaderProgram : public ShaderProgram
{ {
public:
enum { enum {
VERTEX_COORDS_ATTR = 0, VERTEX_COORDS_ATTR = 0,
TEXTURE_COORDS_ATTR = 1, TEXTURE_COORDS_ATTR = 1,
@ -38,22 +38,22 @@ public:
TEXTURE_UNIFORM = 4, TEXTURE_UNIFORM = 4,
TICKS_UNIFORM = 5 TICKS_UNIFORM = 5
}; };
public:
enum DrawMode {
Triangles = GL_TRIANGLES,
TriangleStrip = GL_TRIANGLE_STRIP
};
bool link();
void setProjectionMatrix(GLfloat projectionMatrix[3][3]); void setProjectionMatrix(GLfloat projectionMatrix[3][3]);
void setColor(const Color& color); void setColor(const Color& color);
void setOpacity(GLfloat opacity); void setOpacity(GLfloat opacity);
void setTexture(const TexturePtr& texture); void setTexture(const TexturePtr& texture);
void setVertexCoords(const GLfloat *vertices); void draw(const CoordsBuffer& coordsBuffer, DrawMode drawMode = Triangles);
void setTextureCoords(const GLfloat *textureCoords);
void prepareForDraw();
void drawTriangleStrip(int numVertices);
void drawTriangles(int numVertices);
void releaseFromDraw();
private: private:
Boolean<false> m_mustDisableVertexArray; DrawMode m_drawMode;
Boolean<false> m_mustDisableTexCoordsArray;
}; };
#endif #endif

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@ -39,7 +39,7 @@ public:
bool addShaderFromSourceFile(Shader::ShaderType shaderType, const std::string& sourceFile); bool addShaderFromSourceFile(Shader::ShaderType shaderType, const std::string& sourceFile);
void removeShader(const ShaderPtr& shader); void removeShader(const ShaderPtr& shader);
void removeAllShaders(); void removeAllShaders();
bool link(); virtual bool link();
bool bind(); bool bind();
void release(); void release();
std::string log(); std::string log();

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@ -57,7 +57,7 @@ public:
} }
void clear() { m_buffer.reset(); } void clear() { m_buffer.reset(); }
GLfloat *vertexArray() const { return m_buffer.data(); } GLfloat *vertices() const { return m_buffer.data(); }
int vertexCount() const { return m_buffer.size() / 2; } int vertexCount() const { return m_buffer.size() / 2; }
private: private:

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@ -48,15 +48,7 @@ void Map::draw(const Rect& rect)
program = PainterShaderProgramPtr(new PainterShaderProgram); program = PainterShaderProgramPtr(new PainterShaderProgram);
program->addShaderFromSourceCode(Shader::Vertex, glslMainWithTexCoordsVertexShader + glslPositionOnlyVertexShader); program->addShaderFromSourceCode(Shader::Vertex, glslMainWithTexCoordsVertexShader + glslPositionOnlyVertexShader);
program->addShaderFromSourceFile(Shader::Fragment, "/shadertest.frag"); program->addShaderFromSourceFile(Shader::Fragment, "/shadertest.frag");
program->bindAttributeLocation(VERTEX_COORDS_ATTR, "vertexCoord");
program->bindAttributeLocation(TEXTURE_COORDS_ATTR, "textureCoord");
assert(program->link()); assert(program->link());
program->bindUniformLocation(PainterShaderProgram::PROJECTION_MATRIX_UNIFORM, "projectionMatrix");
program->bindUniformLocation(PainterShaderProgram::TEXTURE_TRANSFORM_MATRIX_UNIFORM, "textureTransformMatrix");
program->bindUniformLocation(PainterShaderProgram::COLOR_UNIFORM, "color");
program->bindUniformLocation(PainterShaderProgram::OPACITY_UNIFORM, "opacity");
program->bindUniformLocation(PainterShaderProgram::TEXTURE_UNIFORM, "texture");
program->bindUniformLocation(PainterShaderProgram::TICKS_UNIFORM, "ticks");
} }
g_painter.setColor(Fw::white); g_painter.setColor(Fw::white);
@ -100,22 +92,11 @@ void Map::draw(const Rect& rect)
m_framebuffer->release(); m_framebuffer->release();
//g_painter.setColor(Fw::white);
//m_framebuffer->draw(rect);
g_painter.setCustomProgram(program);
CoordsBuffer coordsBuffer; g_painter.setColor(Fw::white);
coordsBuffer.addRect(rect, Rect(0,0,m_framebuffer->getTexture()->getSize())); m_framebuffer->draw(rect);
coordsBuffer.cacheVertexArrays(); g_painter.releaseCustomProgram();
program->prepareForDraw();
program->setProjectionMatrix((GLfloat (*)[3])g_painter.getProjectionMatrix());
program->setOpacity(1.0f);
program->setColor(Fw::white);
program->setTexture(m_framebuffer->getTexture());
program->setVertexCoords(coordsBuffer.getVertexCoords());
program->setTextureCoords(coordsBuffer.getTextureCoords());
program->drawTriangles(coordsBuffer.getVertexCount());
program->releaseFromDraw();
// calculate stretch factor // calculate stretch factor
float horizontalStretchFactor = rect.width() / (float)(m_visibleSize.width() * NUM_TILE_PIXELS); float horizontalStretchFactor = rect.width() / (float)(m_visibleSize.width() * NUM_TILE_PIXELS);