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volume-shader-testing
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Signed-off-by: Perminder <[email protected]>
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@perminder-17
perminder-17 committed Jan 13, 2025
1 parent 7e230e3 commit 9236ff9
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Showing 3 changed files with 89 additions and 51 deletions.
4 changes: 4 additions & 0 deletions avogadro/rendering/glrenderer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,7 @@ void GLRenderer::initialize()
}

m_solidPipeline.initialize();

}

void GLRenderer::resize(int width, int height)
Expand Down Expand Up @@ -100,10 +101,13 @@ void GLRenderer::render()
GLRenderVisitor visitor(m_camera, m_textRenderStrategy);
// Setup for solid geometry
m_solidPipeline.begin();
{
visitor.setRenderPass(SolidPass);
glEnable(GL_DEPTH_TEST);
glDisable(GL_BLEND);
m_scene.rootNode().accept(visitor);
m_solidPipeline.renderVolumeFaces(m_camera);
}
m_solidPipeline.end();

// Setup for opaque geometry
Expand Down
16 changes: 8 additions & 8 deletions avogadro/rendering/solid_first_fs.glsl
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ varying vec2 UV;
uniform sampler2D inRGBTex;
uniform sampler2D inFrontDepthTex;
uniform sampler2D inBackDepthTex;

uniform sampler2D transferTex;
// The 3D volume data
uniform sampler3D uVolumeData;

Expand Down Expand Up @@ -47,7 +47,7 @@ void main()
}

// 3) Compute the total “thickness” in normalized [0..1] Z
float thickness = backDepth - frontDepth;
float thickness = (backDepth - frontDepth);

// Step size for the raymarch
float stepSize = thickness / float(numSteps);
Expand All @@ -56,14 +56,14 @@ void main()
vec4 accumulatedColor = vec4(0.0);

// Raymarch from frontDepth to backDepth
for (int i = 0; i < numSteps; i++) {
for (int i = 0; i < 256; i++) {
// Parametric Z coordinate in [frontDepth..backDepth]
float z = frontDepth + (float(i) + 0.5) * stepSize;

// UVW in volume texture: XY from screen, Z in [0..1] (assuming the volume
// is also in [0..1] for that axis). You may need to invert or shift if
// your volume is mapped differently.
vec3 uvw = vec3(UV, -z);
vec3 uvw = vec3(UV, z);

// Sample the raw density or intensity from the volume
float rawVal = texture3D(uVolumeData, uvw).r;
Expand All @@ -74,7 +74,7 @@ void main()

// Fetch a color from the colormap — assume 1D colormap along X,
// picking the center of Y=0.5 if it’s just a 1D gradient stored in a 2D texture
vec4 sampleColor = vec4(1.0,0.0,1.0,0.5);
vec4 sampleColor = texture2D(transferTex, vec2(cval, 0.9));

// Scale alpha if you want the volume to be more or less transparent
// (like your ALPHA_SCALE from the original code)
Expand All @@ -86,8 +86,8 @@ void main()
accumulatedColor.a += sampleColor.a * remainingAlpha;

// Optional early-out if almost fully opaque:
if (accumulatedColor.a >= 0.5)
break;
if (accumulatedColor.a >= 0.95)
break;
}

// 5) (Optional) If you have toggles for AO or edges:
Expand All @@ -103,7 +103,7 @@ void main()
// Similar to “1 - alpha” logic you had:
float oneMinusA = 1.0 - accumulatedColor.a;
vec3 finalRGB = accumulatedColor.rgb + oneMinusA * sceneColor.rgb;
float finalA = sceneColor.a + oneMinusA * accumulatedColor.a;
float finalA = sceneColor.a + oneMinusA * accumulatedColor.a; //This was backwards

// Write out final pixel color
gl_FragColor = vec4(finalRGB, finalA);
Expand Down
120 changes: 77 additions & 43 deletions avogadro/rendering/solidpipeline.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm> // for clamp

namespace Avogadro::Rendering {

Expand Down Expand Up @@ -81,10 +82,24 @@ class SolidPipeline::Private
glUniform1i(backLoc, 5);

// Pass screen size
prog.setUniformValue("width", float(w));
prog.setUniformValue("height", float(h));
// prog.setUniformValue("width", float(w));
// prog.setUniformValue("height", float(h));
}

void attachTransferFunction(ShaderProgram& prog,
const GLchar* tfName, GLuint tfTex)
{
prog.bind();
GLuint programID = 0;
glGetIntegerv(GL_CURRENT_PROGRAM, (GLint*)&programID);

// Bind the transfer function texture on some texture unit (say GL_TEXTURE6)
GLuint loc = glGetUniformLocation(programID, tfName);
glActiveTexture(GL_TEXTURE6);
glBindTexture(GL_TEXTURE_2D, tfTex);
glUniform1i(loc, 6); // tell the sampler that our TF is at unit 6
}

/** Our FBOs and textures. */
GLuint defaultFBO; // The system FBO (screen)
GLuint renderFBO; // Main scene FBO
Expand Down Expand Up @@ -114,6 +129,7 @@ class SolidPipeline::Private
Shader firstFragmentShader;

// Box geometry for front/back pass
GLuint transferTexture;
GLuint volumeBoxVao;
GLuint volumeBoxVbo;
GLuint volumeBoxEbo;
Expand Down Expand Up @@ -147,24 +163,24 @@ static const GLfloat boxVertices[] = {
};

static const GLuint boxIndices[] = {
// Front face
0, 1, 2,
2, 3, 0,
// Back face
4, 5, 6,
6, 7, 4,
// Left face
4, 0, 3,
3, 7, 4,
// Right face
1, 5, 6,
6, 2, 1,
// Top face
3, 2, 6,
6, 7, 3,
// Bottom face
4, 5, 1,
1, 0, 4
// front
0, 1, 2,
0, 2, 3,
// right
1, 5, 6,
1, 6, 2,
// back
5, 4, 7,
5, 7, 6,
// left
4, 0, 3,
4, 3, 7,
// top
2, 6, 7,
2, 7, 3,
// bottom
4, 5, 1,
4, 1, 0,
};

// Helper to create an FBO
Expand All @@ -173,35 +189,21 @@ void initializeFramebuffer(GLuint* outFBO, GLuint* texRGB, GLuint* texDepth)
glGenFramebuffers(1, outFBO);
glBindFramebuffer(GL_FRAMEBUFFER, *outFBO);

// Color
glGenTextures(1, texRGB);
glBindTexture(GL_TEXTURE_2D, *texRGB);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, *texRGB, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
*texRGB, 0);

// Depth
glGenTextures(1, texDepth);
glBindTexture(GL_TEXTURE_2D, *texDepth);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24, 1, 1, 0,
GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, nullptr);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_TEXTURE_2D, *texDepth, 0);

GLenum drawBuffersList[1] = { GL_COLOR_ATTACHMENT0 };
glDrawBuffers(1, drawBuffersList);

if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
std::cerr << "Error: FBO not complete!" << std::endl;
}

glBindFramebuffer(GL_FRAMEBUFFER, 0);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D,
*texDepth, 0);
}

SolidPipeline::SolidPipeline()
Expand All @@ -218,11 +220,16 @@ SolidPipeline::SolidPipeline()

SolidPipeline::~SolidPipeline()
{
if (d->transferTexture) {
glDeleteTextures(1, &d->transferTexture);
d->transferTexture = 0;
}
delete d;
}

void SolidPipeline::initialize()
{
std::cout<<"SolidPipeline::initialize()"<<std::endl;
// 1) Create FBOs
initializeFramebuffer(&d->renderFBO, &d->renderTexture, &d->depthTexture);
initializeFramebuffer(&d->backFBO, &d->backColorTexture, &d->backDepthTexture);
Expand All @@ -237,8 +244,8 @@ void SolidPipeline::initialize()
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

int size = 64;
std::vector<float> volumeData(size * size * size);
int size = 256;
std::vector<float> volumeData(size * size * size, 0.0f);
for (int z = 0; z < size; ++z) {
for (int y = 0; y < size; ++y) {
for (int x = 0; x < size; ++x) {
Expand All @@ -250,11 +257,34 @@ void SolidPipeline::initialize()
}
}
}

glTexImage3D(GL_TEXTURE_3D, 0, GL_R32F,
size, size, size, 0,
GL_RED, GL_FLOAT,
volumeData.data());
std::vector<unsigned char> tfData(256 * 4);
for (int i = 0; i < 256; ++i) {
// i ko [0..255] se normalize karke color aur alpha define
float t = float(i) / 255.0f;
// let’s do a pinkish gradient: RGBA
tfData[i*4 + 0] = static_cast<unsigned char>(255.0f * t); // R
tfData[i*4 + 1] = static_cast<unsigned char>(128.0f * t); // G
tfData[i*4 + 2] = static_cast<unsigned char>(255.0f * (1-t));// B
tfData[i*4 + 3] = static_cast<unsigned char>(255.0f * t); // A
}

glGenTextures(1, &d->transferTexture);
glBindTexture(GL_TEXTURE_2D, d->transferTexture);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

// Upload 256x1 RGBA8
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 1, 0,
GL_RGBA, GL_UNSIGNED_BYTE, tfData.data());
glBindTexture(GL_TEXTURE_2D, 0);
// 3) Create box geometry VAO
glGenVertexArrays(1, &d->volumeBoxVao);
glBindVertexArray(d->volumeBoxVao);
Expand Down Expand Up @@ -318,6 +348,7 @@ void SolidPipeline::initialize()
void SolidPipeline::renderVolumeFaces(const Camera& cam)
{
// Simple approach: use boxShaders to set up MVP

d->boxShaders.bind();

// Get the combined projection * modelView
Expand All @@ -333,6 +364,7 @@ void SolidPipeline::renderVolumeFaces(const Camera& cam)
glViewport(0, 0, m_width, m_height);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
// glDepthFunc(GL_GREATER);
glCullFace(GL_FRONT); // cull front, show back
glClearColor(0.f, 0.f, 0.f, 0.f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Expand All @@ -354,6 +386,7 @@ void SolidPipeline::renderVolumeFaces(const Camera& cam)
glViewport(0, 0, m_width, m_height);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
// glDepthFunc(GL_LESS);
glCullFace(GL_BACK); // cull back, show front
glClearColor(0.f, 0.f, 0.f, 0.f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Expand Down Expand Up @@ -424,6 +457,7 @@ void SolidPipeline::end()
"inBackDepthTex", d->backDepthTexture,
m_width, m_height);

d->attachTransferFunction(d->firstStageShaders, "transferTex", d->transferTexture);
d->firstStageShaders.bind();
// Basic user uniforms
d->firstStageShaders.setUniformValue("inAoEnabled", (m_aoEnabled ? 1.0f : 0.0f));
Expand All @@ -432,7 +466,7 @@ void SolidPipeline::end()
d->firstStageShaders.setUniformValue("transferMin", 0.0f);
d->firstStageShaders.setUniformValue("transferMax", 1.0f);
d->firstStageShaders.setUniformValue("numSteps", 128);
d->firstStageShaders.setUniformValue("alphaScale", 0.02f);
d->firstStageShaders.setUniformValue("alphaScale", 0.1f);

// Bind volume
GLint progID = 0;
Expand Down

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ERROR: clang-format-diff detected formatting issues. See the artifact for a patch or run clang-format on your branch.

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