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forked from 0ad/0ad
0ad/source/renderer/OverlayRenderer.cpp
vts 46a09ced71 Fixed some compilation warnings
This was SVN commit r10710.
2011-12-11 02:11:05 +00:00

712 lines
25 KiB
C++

/* Copyright (C) 2011 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#include "precompiled.h"
#include "OverlayRenderer.h"
#include "maths/MathUtil.h"
#include "maths/Quaternion.h"
#include "maths/Vector2D.h"
#include "graphics/LOSTexture.h"
#include "graphics/Overlay.h"
#include "graphics/Terrain.h"
#include "graphics/TextureManager.h"
#include "lib/ogl.h"
#include "ps/Game.h"
#include "ps/Profile.h"
#include "renderer/Renderer.h"
#include "renderer/VertexBuffer.h"
#include "renderer/VertexBufferManager.h"
#include "simulation2/Simulation2.h"
#include "simulation2/components/ICmpWaterManager.h"
struct OverlayRendererInternals
{
std::vector<SOverlayLine*> lines;
std::vector<SOverlayTexturedLine*> texlines;
std::vector<SOverlaySprite*> sprites;
};
class CTexturedLineRData : public CRenderData
{
public:
CTexturedLineRData(SOverlayTexturedLine* line) :
m_Line(line), m_VB(NULL), m_VBIndices(NULL), m_Raise(.2f)
{ }
~CTexturedLineRData()
{
if (m_VB)
g_VBMan.Release(m_VB);
if (m_VBIndices)
g_VBMan.Release(m_VBIndices);
}
struct SVertex
{
SVertex(CVector3D pos, float u, float v) : m_Position(pos) { m_UVs[0] = u; m_UVs[1] = v; }
CVector3D m_Position;
GLfloat m_UVs[2];
float _padding[3]; // 5 floats up till now, so pad with another 3 floats to get a power of 2
};
cassert(sizeof(SVertex) == 32);
void Update();
/**
* Creates a line cap of the specified type @p endCapType at the end of the segment going in direction @p normal, and appends
* the vertices to @p verticesOut in GL_TRIANGLES order.
*
* @param corner1 One of the two butt-end corner points of the line to which the cap should be attached.
* @param corner2 One of the two butt-end corner points of the line to which the cap should be attached.
* @param normal Normal vector indicating the direction of the segment to which the cap should be attached.
* @param endCapType The type of end cap to produce.
* @param verticesOut Output vector of vertices for passing to the renderer.
* @param indicesOut Output vector of vertex indices for passing to the renderer.
*/
void CreateLineCap(const CVector3D& corner1, const CVector3D& corner2, const CVector3D& normal,
SOverlayTexturedLine::LineCapType endCapType, std::vector<SVertex>& verticesOut, std::vector<u16>& indicesOut);
/// Small utility function; grabs the centroid of the positions of two vertices
inline CVector3D Centroid(const SVertex& v1, const SVertex& v2)
{
return (v1.m_Position + v2.m_Position) * 0.5;
}
SOverlayTexturedLine* m_Line;
CVertexBuffer::VBChunk* m_VB;
CVertexBuffer::VBChunk* m_VBIndices;
float m_Raise; // small vertical offset of line from terrain to prevent visual glitches
};
OverlayRenderer::OverlayRenderer()
{
m = new OverlayRendererInternals();
}
OverlayRenderer::~OverlayRenderer()
{
delete m;
}
void OverlayRenderer::Submit(SOverlayLine* line)
{
ENSURE(line->m_Coords.size() % 3 == 0);
m->lines.push_back(line);
}
void OverlayRenderer::Submit(SOverlayTexturedLine* line)
{
// Simplify the rest of the code by guaranteeing non-empty lines
if (line->m_Coords.empty())
return;
ENSURE(line->m_Coords.size() % 2 == 0);
m->texlines.push_back(line);
}
void OverlayRenderer::Submit(SOverlaySprite* overlay)
{
m->sprites.push_back(overlay);
}
void OverlayRenderer::EndFrame()
{
m->lines.clear();
m->texlines.clear();
m->sprites.clear();
// this should leave the capacity unchanged, which is okay since it
// won't be very large or very variable
}
void OverlayRenderer::PrepareForRendering()
{
PROFILE3("prepare overlays");
// This is where we should do something like sort the overlays by
// colour/sprite/etc for more efficient rendering
for (size_t i = 0; i < m->texlines.size(); ++i)
{
SOverlayTexturedLine* line = m->texlines[i];
if (!line->m_RenderData)
{
line->m_RenderData = shared_ptr<CRenderData>(new CTexturedLineRData(line));
static_cast<CTexturedLineRData*>(line->m_RenderData.get())->Update();
// We assume the overlay line will get replaced by the caller
// if terrain changes, so we don't need to detect that here and
// call Update again. Also we assume the caller won't change
// any of the parameters after first submitting the line.
}
}
}
void OverlayRenderer::RenderOverlaysBeforeWater()
{
PROFILE3_GPU("overlays (before)");
glDisable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
for (size_t i = 0; i < m->lines.size(); ++i)
{
SOverlayLine* line = m->lines[i];
if (line->m_Coords.empty())
continue;
ENSURE(line->m_Coords.size() % 3 == 0);
glColor4fv(line->m_Color.FloatArray());
glLineWidth((float)line->m_Thickness);
glInterleavedArrays(GL_V3F, sizeof(float)*3, &line->m_Coords[0]);
glDrawArrays(GL_LINE_STRIP, 0, (GLsizei)line->m_Coords.size()/3);
}
glDisableClientState(GL_VERTEX_ARRAY);
glLineWidth(1.f);
glDisable(GL_BLEND);
}
void OverlayRenderer::RenderOverlaysAfterWater()
{
PROFILE3_GPU("overlays (after)");
if (!m->texlines.empty())
{
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glDepthMask(0);
const char* shaderName;
if (g_Renderer.GetRenderPath() == CRenderer::RP_SHADER)
shaderName = "overlayline";
else
shaderName = "fixed:overlayline";
std::map<CStr, CStr> defAlwaysVisible;
defAlwaysVisible.insert(std::make_pair(CStr("IGNORE_LOS"), CStr("1")));
CLOSTexture& los = g_Renderer.GetScene().GetLOSTexture();
CShaderManager& shaderManager = g_Renderer.GetShaderManager();
CShaderProgramPtr shaderTexLineNormal(shaderManager.LoadProgram(shaderName, std::map<CStr, CStr>()));
CShaderProgramPtr shaderTexLineAlwaysVisible(shaderManager.LoadProgram(shaderName, defAlwaysVisible));
// ----------------------------------------------------------------------------------------
shaderTexLineNormal->Bind();
shaderTexLineNormal->BindTexture("losTex", los.GetTexture());
shaderTexLineNormal->Uniform("losTransform", los.GetTextureMatrix()[0], los.GetTextureMatrix()[12], 0.f, 0.f);
// batch render only the non-always-visible overlay lines using the normal shader
RenderTexturedOverlayLines(shaderTexLineNormal, false);
shaderTexLineNormal->Unbind();
// ----------------------------------------------------------------------------------------
shaderTexLineAlwaysVisible->Bind();
// TODO: losTex and losTransform are unused in the always visible shader, but I'm not sure if it's worthwhile messing
// with it just to remove these calls
shaderTexLineAlwaysVisible->BindTexture("losTex", los.GetTexture());
shaderTexLineAlwaysVisible->Uniform("losTransform", los.GetTextureMatrix()[0], los.GetTextureMatrix()[12], 0.f, 0.f);
// batch render only the always-visible overlay lines using the LoS-ignored shader
RenderTexturedOverlayLines(shaderTexLineAlwaysVisible, true);
shaderTexLineAlwaysVisible->Unbind();
// TODO: the shader should probably be responsible for unbinding its textures
g_Renderer.BindTexture(1, 0);
g_Renderer.BindTexture(0, 0);
CVertexBuffer::Unbind();
glDisableClientState(GL_VERTEX_ARRAY);
pglClientActiveTextureARB(GL_TEXTURE1);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
pglClientActiveTextureARB(GL_TEXTURE0);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDepthMask(1);
glDisable(GL_BLEND);
}
}
void OverlayRenderer::RenderTexturedOverlayLines(CShaderProgramPtr shaderTexLine, bool alwaysVisible)
{
int streamflags = shaderTexLine->GetStreamFlags();
if (streamflags & STREAM_POS)
glEnableClientState(GL_VERTEX_ARRAY);
if (streamflags & STREAM_UV0)
{
pglClientActiveTextureARB(GL_TEXTURE0);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
}
if (streamflags & STREAM_UV1)
{
pglClientActiveTextureARB(GL_TEXTURE1);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
}
for (size_t i = 0; i < m->texlines.size(); ++i)
{
SOverlayTexturedLine* line = m->texlines[i];
// render only those lines matching the requested alwaysVisible status
if (!line->m_RenderData || line->m_AlwaysVisible != alwaysVisible)
continue;
shaderTexLine->BindTexture("baseTex", line->m_TextureBase->GetHandle());
shaderTexLine->BindTexture("maskTex", line->m_TextureMask->GetHandle());
shaderTexLine->Uniform("objectColor", line->m_Color);
CTexturedLineRData* rdata = static_cast<CTexturedLineRData*>(line->m_RenderData.get());
if (!rdata->m_VB || !rdata->m_VBIndices)
continue; // might have failed to allocate
// -- render main line quad strip ----------------------
GLsizei stride = sizeof(CTexturedLineRData::SVertex);
CTexturedLineRData::SVertex* vertexBase = reinterpret_cast<CTexturedLineRData::SVertex*>(rdata->m_VB->m_Owner->Bind());
if (streamflags & STREAM_POS)
glVertexPointer(3, GL_FLOAT, stride, &vertexBase->m_Position[0]);
if (streamflags & STREAM_UV0)
{
pglClientActiveTextureARB(GL_TEXTURE0);
glTexCoordPointer(2, GL_FLOAT, stride, &vertexBase->m_UVs[0]);
}
if (streamflags & STREAM_UV1)
{
pglClientActiveTextureARB(GL_TEXTURE1);
glTexCoordPointer(2, GL_FLOAT, stride, &vertexBase->m_UVs[0]);
}
u8* indexBase = rdata->m_VBIndices->m_Owner->Bind();
glDrawElements(GL_TRIANGLES, rdata->m_VBIndices->m_Count, GL_UNSIGNED_SHORT, indexBase + sizeof(u16)*rdata->m_VBIndices->m_Index);
g_Renderer.GetStats().m_OverlayTris += rdata->m_VBIndices->m_Count/3;
}
}
void OverlayRenderer::RenderForegroundOverlays(const CCamera& viewCamera)
{
PROFILE3_GPU("overlays (fg)");
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glDisable(GL_DEPTH_TEST);
CVector3D right = -viewCamera.m_Orientation.GetLeft();
CVector3D up = viewCamera.m_Orientation.GetUp();
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
float uvs[8] = { 0,0, 1,0, 1,1, 0,1 };
glTexCoordPointer(2, GL_FLOAT, sizeof(float)*2, &uvs);
for (size_t i = 0; i < m->sprites.size(); ++i)
{
SOverlaySprite* sprite = m->sprites[i];
sprite->m_Texture->Bind();
CVector3D pos[4] = {
sprite->m_Position + right*sprite->m_X0 + up*sprite->m_Y0,
sprite->m_Position + right*sprite->m_X1 + up*sprite->m_Y0,
sprite->m_Position + right*sprite->m_X1 + up*sprite->m_Y1,
sprite->m_Position + right*sprite->m_X0 + up*sprite->m_Y1
};
glVertexPointer(3, GL_FLOAT, sizeof(float)*3, &pos[0].X);
glDrawArrays(GL_QUADS, 0, (GLsizei)4);
}
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_DEPTH_TEST);
glDisable(GL_BLEND);
glDisable(GL_TEXTURE_2D);
}
void CTexturedLineRData::Update()
{
if (m_VB)
{
g_VBMan.Release(m_VB);
m_VB = NULL;
}
if (m_VBIndices)
{
g_VBMan.Release(m_VBIndices);
m_VBIndices = NULL;
}
CTerrain* terrain = m_Line->m_Terrain;
CmpPtr<ICmpWaterManager> cmpWaterManager(*g_Game->GetSimulation2(), SYSTEM_ENTITY);
float v = 0.f;
std::vector<SVertex> vertices;
std::vector<u16> indices;
size_t n = m_Line->m_Coords.size() / 2; // number of line points
bool closed = m_Line->m_Closed;
ENSURE(n >= 2); // minimum needed to avoid errors (also minimum value to make sense, can't draw a line between 1 point)
// In each iteration, p1 is the position of vertex i, p0 is i-1, p2 is i+1.
// To avoid slightly expensive terrain computations we cycle these around and
// recompute p2 at the end of each iteration.
CVector3D p0;
CVector3D p1(m_Line->m_Coords[0], 0, m_Line->m_Coords[1]);
CVector3D p2(m_Line->m_Coords[(1 % n)*2], 0, m_Line->m_Coords[(1 % n)*2+1]);
if (closed)
// grab the ending point so as to close the loop
p0 = CVector3D(m_Line->m_Coords[(n-1)*2], 0, m_Line->m_Coords[(n-1)*2+1]);
else
// we don't want to loop around and use the direction towards the other end of the line, so create an artificial p0 that
// extends the p2 -> p1 direction, and use that point instead
p0 = p1 + (p1 - p2);
bool p1floating = false;
bool p2floating = false;
// Compute terrain heights, clamped to the water height (and remember whether
// each point was floating on water, for normal computation later)
// TODO: if we ever support more than one water level per map, recompute this per point
float w = cmpWaterManager->GetExactWaterLevel(p0.X, p0.Z);
p0.Y = terrain->GetExactGroundLevel(p0.X, p0.Z);
if (p0.Y < w)
p0.Y = w;
p1.Y = terrain->GetExactGroundLevel(p1.X, p1.Z);
if (p1.Y < w)
{
p1.Y = w;
p1floating = true;
}
p2.Y = terrain->GetExactGroundLevel(p2.X, p2.Z);
if (p2.Y < w)
{
p2.Y = w;
p2floating = true;
}
for (size_t i = 0; i < n; ++i)
{
// For vertex i, compute bisector of lines (i-1)..(i) and (i)..(i+1)
// perpendicular to terrain normal
// Normal is vertical if on water, else computed from terrain
CVector3D norm;
if (p1floating)
norm = CVector3D(0, 1, 0);
else
norm = m_Line->m_Terrain->CalcExactNormal(p1.X, p1.Z);
CVector3D b = ((p1 - p0).Normalized() + (p2 - p1).Normalized()).Cross(norm);
// Adjust bisector length to match the line thickness, along the line's width
float l = b.Dot((p2 - p1).Normalized().Cross(norm));
if (fabs(l) > 0.000001f) // avoid unlikely divide-by-zero
b *= m_Line->m_Thickness / l;
// Push vertices and indices in GL_TRIANGLES order
//
// NOTE: in order for OpenGL to successfully render these, the winding order needs to be correct. Basically, it means
// that every pair of triangles sharing a side must specify the vertices of that side in the opposite order from the
// other triangle.
// (see http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node16.html for an illustration)
//
// What the code below does is push the indices for a quad composed of two triangles in each iteration. The two triangles
// of each quad are indexed using the winding orders (BR, BL, TR) and (TR, BL, TR) (where BR is bottom-right of this
// iteration's quad, TR top-right etc).
SVertex vertex1(p1 + b + norm*m_Raise, 0.f, v);
SVertex vertex2(p1 - b + norm*m_Raise, 1.f, v);
vertices.push_back(vertex1);
vertices.push_back(vertex2);
u16 index1 = vertices.size() - 2; // index of vertex1 in this iteration (TR of this quad)
u16 index2 = vertices.size() - 1; // index of the vertex2 in this iteration (TL of this quad)
if (i == 0)
{
// initial two vertices to continue building triangles from (n must be >= 2 for this to work)
indices.push_back(index1);
indices.push_back(index2);
}
else
{
u16 index1Prev = vertices.size() - 4; // index of the vertex1 in the previous iteration (BR of this quad)
u16 index2Prev = vertices.size() - 3; // index of the vertex2 in the previous iteration (BL of this quad)
ENSURE(index1Prev < vertices.size());
ENSURE(index2Prev < vertices.size());
// Add two corner points from last iteration and join with one of our own corners to create triangle 1
// (don't need to do this if i == 1 because i == 0 are the first two ones, they don't need to be copied)
if (i > 1)
{
indices.push_back(index1Prev);
indices.push_back(index2Prev);
}
indices.push_back(index1); // complete triangle 1
// create triangle 2, specifying the adjacent side's vertices in the opposite order from triangle 1
indices.push_back(index1);
indices.push_back(index2Prev);
indices.push_back(index2);
}
// alternate V coordinate for debugging
v = 1 - v;
// cycle the p's and compute the new p2
p0 = p1;
p1 = p2;
p1floating = p2floating;
// if in closed mode, wrap around the coordinate array for p2 -- otherwise, extend linearly
if (!closed && i == n-2)
// next iteration is the last point of the line, so create an artificial p2 that extends the p0 -> p1 direction
p2 = p1 + (p1 - p0);
else
p2 = CVector3D(m_Line->m_Coords[((i+2) % n)*2], 0, m_Line->m_Coords[((i+2) % n)*2+1]);
p2.Y = terrain->GetExactGroundLevel(p2.X, p2.Z);
if (p2.Y < w)
{
p2.Y = w;
p2floating = true;
}
else
p2floating = false;
}
if (closed)
{
// close the path
indices.push_back(vertices.size()-2);
indices.push_back(vertices.size()-1);
indices.push_back(0);
indices.push_back(0);
indices.push_back(vertices.size()-1);
indices.push_back(1);
}
else
{
// Create start and end caps. On either end, this is done by taking the centroid between the last and second-to-last pair of
// vertices that was generated along the path (i.e. the vertex1's and vertex2's from above), taking a directional vector
// between them, and drawing the line cap in the plane given by the two butt-end corner points plus said vector.
std::vector<u16> capIndices;
std::vector<SVertex> capVertices;
// create end cap
CreateLineCap(
// the order of these vertices is important here, swapping them produces caps at the wrong side
vertices[vertices.size()-2].m_Position, // top-right vertex of last quad
vertices[vertices.size()-1].m_Position, // top-left vertex of last quad
// directional vector between centroids of last vertex pair and second-to-last vertex pair
(Centroid(vertices[vertices.size()-2], vertices[vertices.size()-1]) - Centroid(vertices[vertices.size()-4], vertices[vertices.size()-3])).Normalized(),
m_Line->m_EndCapType,
capVertices,
capIndices
);
for (unsigned i = 0; i < capIndices.size(); i++)
capIndices[i] += vertices.size();
vertices.insert(vertices.end(), capVertices.begin(), capVertices.end());
indices.insert(indices.end(), capIndices.begin(), capIndices.end());
capIndices.clear();
capVertices.clear();
// create start cap
CreateLineCap(
// the order of these vertices is important here, swapping them produces caps at the wrong side
vertices[1].m_Position,
vertices[0].m_Position,
// directional vector between centroids of first vertex pair and second vertex pair
(Centroid(vertices[1], vertices[0]) - Centroid(vertices[3], vertices[2])).Normalized(),
m_Line->m_StartCapType,
capVertices,
capIndices
);
for (unsigned i = 0; i < capIndices.size(); i++)
capIndices[i] += vertices.size();
vertices.insert(vertices.end(), capVertices.begin(), capVertices.end());
indices.insert(indices.end(), capIndices.begin(), capIndices.end());
}
ENSURE(indices.size() % 3 == 0); // GL_TRIANGLES indices, so must be multiple of 3
m_VB = g_VBMan.Allocate(sizeof(SVertex), vertices.size(), GL_STATIC_DRAW, GL_ARRAY_BUFFER);
if (m_VB)
{
// allocation might fail (e.g. due to too many vertices)
m_VB->m_Owner->UpdateChunkVertices(m_VB, &vertices[0]); // copy data into VBO
for (size_t k = 0; k < indices.size(); ++k)
indices[k] += m_VB->m_Index;
m_VBIndices = g_VBMan.Allocate(sizeof(u16), indices.size(), GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);
if (m_VBIndices)
m_VBIndices->m_Owner->UpdateChunkVertices(m_VBIndices, &indices[0]);
}
}
void CTexturedLineRData::CreateLineCap(const CVector3D& corner1, const CVector3D& corner2, const CVector3D& lineDirectionNormal,
SOverlayTexturedLine::LineCapType endCapType, std::vector<SVertex>& verticesOut,
std::vector<u16>& indicesOut)
{
if (endCapType == SOverlayTexturedLine::LINECAP_FLAT)
return; // no action needed, this is the default
// When not in closed mode, we've created artificial points for the start- and endpoints that extend the line in the
// direction of the first and the last segment, respectively. Thus, we know both the start and endpoints have perpendicular
// butt endings, i.e. the end corner vertices on either side of the line extend perpendicularly from the segment direction.
// That is to say, when viewed from the top, we will have something like
// .
// this: and not like this: /|
// ____. / |
// | / .
// | /
// ____. /
//
int roundCapPoints = 8; // amount of points to sample along the semicircle for rounded caps (including corner points)
float radius = m_Line->m_Thickness;
CVector3D centerPoint = (corner1 + corner2) * 0.5f;
SVertex centerVertex(centerPoint, 0.5f, 0.5f);
u16 indexOffset = verticesOut.size(); // index offset in verticesOut from where we start adding our vertices
switch (endCapType)
{
case SOverlayTexturedLine::LINECAP_SHARP:
{
roundCapPoints = 3; // creates only one point directly ahead
radius *= 1.5f; // make it a bit sharper (note that we don't use the radius for the butt-end corner points so it should be ok)
centerVertex.m_UVs[0] = 0.480f; // slight visual correction to make the texture match up better at the corner points
}
// fall-through
case SOverlayTexturedLine::LINECAP_ROUND:
{
// Draw a rounded line cap in the 3D plane of the line specified by the two corner points and the normal vector of the
// line's direction. The terrain normal at the centroid between the two corner points is perpendicular to this plane.
// The way this works is by taking a vector from the corner points' centroid to one of the corner points (which is then
// of radius length), and rotate it around the terrain normal vector in that centroid. This will rotate the vector in
// the line's plane, producing the desired rounded cap.
// To please OpenGL's winding order, this angle needs to be negated depending on whether we start rotating from
// the (center -> corner1) or (center -> corner2) vector. For the (center -> corner2) vector, we apparently need to use
// the negated angle.
float stepAngle = -(float)(M_PI/(roundCapPoints-1));
// Push the vertices in triangle fan order (easy to generate GL_TRIANGLES indices for afterwards)
// Note that we're manually adding the corner vertices instead of having them be generated by the rotating vector.
// This is because we want to support an overly large radius to make the sharp line ending look sharper.
verticesOut.push_back(centerVertex);
verticesOut.push_back(SVertex(corner2, 0.f, 0.f));
// Get the base vector that we will incrementally rotate in the cap plane to produce the radial sample points.
// Normally corner2 - centerPoint would suffice for this since it is of radius length, but we want to support custom
// radii to support tuning the 'sharpness' of sharp end caps (see above)
CVector3D rotationBaseVector = (corner2 - centerPoint).Normalized() * radius;
// Calculate the normal vector of the plane in which we're going to be drawing the line cap. This is the vector that
// is perpendicular to both baseVector and the 'lineDirectionNormal' vector indicating the direction of the line.
// Note that we shouldn't use terrain->CalcExactNormal() here because if the line is being rendered on top of water,
// then CalcExactNormal will return the normal vector of the terrain that's underwater (which can be quite funky).
CVector3D capPlaneNormal = lineDirectionNormal.Cross(rotationBaseVector).Normalized();
for (int i = 1; i < roundCapPoints - 1; ++i)
{
// Rotate the centerPoint -> corner vector by i*stepAngle radians around the cap plane normal at the center point.
CQuaternion quatRotation;
quatRotation.FromAxisAngle(capPlaneNormal, i * stepAngle);
CVector3D worldPos3D = centerPoint + quatRotation.Rotate(rotationBaseVector);
// Let v range from 0 to 1 as we move along the semi-circle, keep u fixed at 0 (i.e. curve the left vertical edge
// of the texture around the edge of the semicircle)
float u = 0.f;
float v = clamp((i/(float)(roundCapPoints-1)), 0.f, 1.f); // pos, u, v
verticesOut.push_back(SVertex(worldPos3D, u, v));
}
// connect back to the other butt-end corner point to complete the semicircle
verticesOut.push_back(SVertex(corner1, 0.f, 1.f));
// now push indices in GL_TRIANGLES order; vertices[indexOffset] is the center vertex, vertices[indexOffset + 1] is the
// first corner point, then a bunch of radial samples, and then at the end we have the other corner point again. So:
for (int i=1; i < roundCapPoints; ++i)
{
indicesOut.push_back(indexOffset); // center vertex
indicesOut.push_back(indexOffset + i);
indicesOut.push_back(indexOffset + i + 1);
}
}
break;
case SOverlayTexturedLine::LINECAP_SQUARE:
{
// Extend the (corner1 -> corner2) vector along the direction normal and draw a square line ending consisting of
// three triangles (sort of like a triangle fan)
// NOTE: The order in which the vertices are pushed out determines the visibility, as they
// are rendered only one-sided; the wrong order of vertices will make the cap visible only from the bottom.
verticesOut.push_back(centerVertex);
verticesOut.push_back(SVertex(corner2, 0.f, 0.f));
verticesOut.push_back(SVertex(corner2 + (lineDirectionNormal * (m_Line->m_Thickness)), 0.f, 0.33333f)); // extend butt corner point 2 along the normal vector
verticesOut.push_back(SVertex(corner1 + (lineDirectionNormal * (m_Line->m_Thickness)), 0.f, 0.66666f)); // extend butt corner point 1 along the normal vector
verticesOut.push_back(SVertex(corner1, 0.f, 1.0f)); // push butt corner point 1
for (int i=1; i < 4; ++i)
{
indicesOut.push_back(indexOffset); // center point
indicesOut.push_back(indexOffset + i);
indicesOut.push_back(indexOffset + i + 1);
}
}
break;
default:
break;
}
}