I'm trying to port this shadertoy into OpenGL https://www.shadertoy.com/view/7lBBR3
Shadertoday has a vec4 fragCoord and a vec3 iResolution; that I'm not sure how to translate into my OpenGL shader.
I have a 2D plane that is projeted like this:
glm::vec3 camera = {0.f, 0.f, -5.f};
glm::vec3 projection = glm::perspective(glm::radians(45.f), app.aspectRatio, 0.1f, 100.f);
projection = glm::scale(projection, {1.f, -1.f, 1.f});
glm::mat view = glm::translate(projection, camera);
And then my vertex shader uses this view like this
layout(location = 0) in vec2 vPosition;
layout(location = 1) in vec2 vTexturePosition;
layout(location = 0) out vec2 position;
layout(location = 1) out vec2 texturePosition;
layout(binding = 0) uniform ubo {
mat4 uView;
};
void main() {
gl_Position = uView * vec4(vPosition, 0.f, 1.f);
texturePosition = vTexturePosition;
}
So now is where I'm not sure how to proceed, in the shadertoy shader you can see lines like this
vec3 planeposition = vec3(fragCoord.xy / iResolution.y, 0.0);
vec2 cursorposition = iMouse.xy / iResolution.y;
vec2 uv = fract(fragCoord.xy / iResolution.y);
vec2 noise = fract(fragCoord.xy * 0.5);
Since I'm using a projection matrix I don't think iResolution is relevant, since it's just the size in pixels of the viewport.
Also, fragCoord what it is? Is my vPosition from the vertex buffer?
Shadertoy's shaders are designed for a screen space render pass. iResolution is always the size of the viewport. iMouse is the window coordinate of the mouse pointer. fragCoord is the same as the fragment shader built-in uniform gl_FragCoord. So if your rectangles cover the entire viewport, you just need to create and set the iResolution and iMouse uniforms and replace fragCoord with gl_FragCoord.
Note that you cannot omit iResolution entirely, as it also includes the aspect ratio of the viewport.
Related
I have been playing around with OpenGL and shaders and got myself into shadow mapping.
Trying to follow tutorials on the Internet (ogldev and learnopengl), got some unexpected results.
The issue is best described with few screenshots (I have added a static quad with depth framebuffer for debugging):
Somehow I managed to get shadows to be rendered on a ground quad once, with a static light (this commit). But the shadow pattern is, again, incorrect. I strongly suspect model transformation matrix calculaitons on this:
The way I render the scene is quite straightforward:
create the pipelines:
for mapping the shadows (filling the depth frame buffer)
for rendering the scene using the depth frame buffer
(extra) debugging one, rendering depth frame buffer to a static quad on a screen
fill the depth frame buffer: using the shadow mapping pipeline, render the scene from the light point, using orthographic projection
render the shaded scene: using the rendering pipeline and depth frame buffer bind as the first texture, render the scene from a camera point, using perspective projection
Seems like the algorithm in all those tutorials on shadow mapping out there. Yet, instead of a mouray effect (like in all of the tutorials), I get no shadow on the bottom plane whatsoever and weird artifacts (incorrect shadow mapping) on the 3D (chicken) model.
Interestingly enough, if I do not render (for both the shadow mapping and final rendering pass) the chicken model, the plane is lit with the same weird pattern:
I also had to remove any normal transformations from the fragment shader and disable face culling to make the ground plane lit. With front-face culling the plane does not appear in the shadow map (depth buffer).
I assume the following might be causing this issue:
wrong depth frame buffer setup (data format or texture parameters)
flipped depth frame buffer texture
wrong shadow calculations in rendering shaders
wrong light matrices (view & projection) setup
wrong matrix calculations in the rendering shaders (given the model transformation matrices for both chicken model and the quad contain both rotation and scaling)
Unfortunately, I ran out of ideas even on how to assess the above assumptions.
Looking for any help on the matter (also feel free to criticize any of my approaches, including C++, CMake, OpenGL and computer graphics).
The full solution source code is available on GitHub, but for convenience I have placed the heavily cut source code below.
shadow-mapping.vert:
#version 410
layout (location = 0) in vec3 vertexPosition;
out gl_PerVertex
{
vec4 gl_Position;
};
uniform mat4 lightSpaceMatrix;
uniform mat4 modelTransformation;
void main()
{
gl_Position = lightSpaceMatrix * modelTransformation * vec4(vertexPosition, 1.0);
}
shadow-mapping.frag:
#version 410
layout (location = 0) out float fragmentDepth;
void main()
{
fragmentDepth = gl_FragCoord.z;
}
shadow-rendering.vert:
#version 410
layout (location = 0) in vec3 vertexPosition;
layout (location = 1) in vec3 vertexNormal;
layout (location = 2) in vec2 vertexTextureCoord;
out VS_OUT
{
vec3 fragmentPosition;
vec3 normal;
vec2 textureCoord;
vec4 fragmentPositionInLightSpace;
} vsOut;
out gl_PerVertex {
vec4 gl_Position;
};
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
uniform mat4 lightSpaceMatrix;
void main()
{
vsOut.fragmentPosition = vec3(model * vec4(vertexPosition, 1.0));
vsOut.normal = transpose(inverse(mat3(model))) * vertexNormal;
vsOut.textureCoord = vertexTextureCoord;
vsOut.fragmentPositionInLightSpace = lightSpaceMatrix * model * vec4(vertexPosition, 1.0);
gl_Position = projection * view * model * vec4(vertexPosition, 1.0);
}
shadow-rendering.frag:
#version 410
layout (location = 0) out vec4 fragmentColor;
in VS_OUT {
vec3 fragmentPosition;
vec3 normal;
vec2 textureCoord;
vec4 fragmentPositionInLightSpace;
} fsIn;
uniform sampler2D shadowMap;
uniform sampler2D diffuseTexture;
uniform vec3 lightPosition;
uniform vec3 lightColor;
uniform vec3 cameraPosition;
float shadowCalculation()
{
vec2 shadowMapCoord = fsIn.fragmentPositionInLightSpace.xy * 0.5 + 0.5;
float occluderDepth = texture(shadowMap, shadowMapCoord).r;
float thisDepth = fsIn.fragmentPositionInLightSpace.z * 0.5 + 0.5;
return occluderDepth < thisDepth ? 1.0 : 0.0;
}
void main()
{
vec3 color = texture(diffuseTexture, fsIn.textureCoord).rgb;
vec3 normal = normalize(fsIn.normal);
// ambient
vec3 ambient = 0.3 * color;
// diffuse
vec3 lightDirection = normalize(lightPosition - fsIn.fragmentPosition);
float diff = max(dot(lightDirection, normal), 0.0);
vec3 diffuse = diff * lightColor;
// specular
vec3 viewDirection = normalize(cameraPosition - fsIn.fragmentPosition);
vec3 halfwayDirection = normalize(lightDirection + viewDirection);
float spec = pow(max(dot(normal, halfwayDirection), 0.0), 64.0);
vec3 specular = spec * lightColor;
// calculate shadow
float shadow = shadowCalculation();
vec3 lighting = ((shadow * (diffuse + specular)) + ambient) * color;
fragmentColor = vec4(lighting, 1.0);
}
main.cpp, setting up shaders and frame buffer:
// loading the shadow mapping shaders
auto shadowMappingVertexProgram = ...;
auto shadowMappingFragmentProgram = ...;
auto shadowMappingLightSpaceUniform = shadowMappingVertexProgram->getUniform<glm::mat4>("lightSpaceMatrix");
auto shadowMappingModelTransformationUniform = shadowMappingVertexProgram->getUniform<glm::mat4>("modelTransformation");
auto shadowMappingPipeline = std::make_unique<globjects::ProgramPipeline>();
shadowMappingPipeline->useStages(shadowMappingVertexProgram.get(), gl::GL_VERTEX_SHADER_BIT);
shadowMappingPipeline->useStages(shadowMappingFragmentProgram.get(), gl::GL_FRAGMENT_SHADER_BIT);
// (omitted) loading the depth frame buffer debugging shaders and creating a pipeline here
// loading the rendering shaders
auto shadowRenderingVertexProgram = ...;
auto shadowRenderingFragmentProgram = ...;
auto shadowRenderingModelTransformationUniform = shadowRenderingVertexProgram->getUniform<glm::mat4>("model");
auto shadowRenderingViewTransformationUniform = shadowRenderingVertexProgram->getUniform<glm::mat4>("view");
auto shadowRenderingProjectionTransformationUniform = shadowRenderingVertexProgram->getUniform<glm::mat4>("projection");
auto shadowRenderingLightSpaceMatrixUniform = shadowRenderingVertexProgram->getUniform<glm::mat4>("lightSpaceMatrix");
auto shadowRenderingLightPositionUniform = shadowRenderingFragmentProgram->getUniform<glm::vec3>("lightPosition");
auto shadowRenderingLightColorUniform = shadowRenderingFragmentProgram->getUniform<glm::vec3>("lightColor");
auto shadowRenderingCameraPositionUniform = shadowRenderingFragmentProgram->getUniform<glm::vec3>("cameraPosition");
auto shadowRenderingPipeline = std::make_unique<globjects::ProgramPipeline>();
shadowRenderingPipeline->useStages(shadowRenderingVertexProgram.get(), gl::GL_VERTEX_SHADER_BIT);
shadowRenderingPipeline->useStages(shadowRenderingFragmentProgram.get(), gl::GL_FRAGMENT_SHADER_BIT);
// loading the chicken model
auto chickenModel = Model::fromAiNode(chickenScene, chickenScene->mRootNode, { "media" });
// INFO: this transformation is hard-coded specifically for Chicken.3ds model
chickenModel->setTransformation(glm::rotate(glm::scale(glm::mat4(1.0f), glm::vec3(0.01f)), glm::radians(-90.0f), glm::vec3(1.0f, 0, 0)));
// loading the quad model
auto quadModel = Model::fromAiNode(quadScene, quadScene->mRootNode);
// INFO: this transformation is hard-coded specifically for quad.obj model
quadModel->setTransformation(glm::rotate(glm::scale(glm::translate(glm::mat4(1.0f), glm::vec3(-5, 0, 5)), glm::vec3(10.0f, 0, 10.0f)), glm::radians(-90.0f), glm::vec3(1.0f, 0, 0)));
// loading the floor texture
sf::Image textureImage = ...;
auto defaultTexture = std::make_unique<globjects::Texture>(static_cast<gl::GLenum>(GL_TEXTURE_2D));
defaultTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_MIN_FILTER), static_cast<GLint>(GL_LINEAR));
defaultTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_MAG_FILTER), static_cast<GLint>(GL_LINEAR));
defaultTexture->image2D(0, static_cast<gl::GLenum>(GL_RGBA8), glm::vec2(textureImage.getSize().x, textureImage.getSize().y), 0, static_cast<gl::GLenum>(GL_RGBA), static_cast<gl::GLenum>(GL_UNSIGNED_BYTE), reinterpret_cast<const gl::GLvoid*>(textureImage.getPixelsPtr()));
// initializing the depth frame buffer
auto shadowMapTexture = std::make_unique<globjects::Texture>(static_cast<gl::GLenum>(GL_TEXTURE_2D));
shadowMapTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_MIN_FILTER), static_cast<gl::GLenum>(GL_LINEAR));
shadowMapTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_MAG_FILTER), static_cast<gl::GLenum>(GL_LINEAR));
shadowMapTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_WRAP_S), static_cast<gl::GLenum>(GL_CLAMP_TO_BORDER));
shadowMapTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_WRAP_T), static_cast<gl::GLenum>(GL_CLAMP_TO_BORDER));
shadowMapTexture->setParameter(static_cast<gl::GLenum>(GL_TEXTURE_BORDER_COLOR), glm::vec4(1.0f, 1.0f, 1.0f, 1.0f));
shadowMapTexture->image2D(0, static_cast<gl::GLenum>(GL_DEPTH_COMPONENT), glm::vec2(window.getSize().x, window.getSize().y), 0, static_cast<gl::GLenum>(GL_DEPTH_COMPONENT), static_cast<gl::GLenum>(GL_FLOAT), nullptr);
auto framebuffer = std::make_unique<globjects::Framebuffer>();
framebuffer->attachTexture(static_cast<gl::GLenum>(GL_DEPTH_ATTACHMENT), shadowMapTexture.get());
main.cpp, rendering (main loop):
// (omitted) event handling, camera updates go here
glm::mat4 cameraProjection = glm::perspective(glm::radians(fov), (float) window.getSize().x / (float) window.getSize().y, 0.1f, 100.0f);
glm::mat4 cameraView = glm::lookAt(cameraPos, cameraPos + cameraForward, cameraUp);
// moving light together with the camera, for debugging purposes
glm::vec3 lightPosition = cameraPos;
// light settings
const float nearPlane = 1.0f;
const float farPlane = 10.0f;
glm::mat4 lightProjection = glm::ortho(-5.0f, 5.0f, -5.0f, 5.0f, nearPlane, farPlane);
glm::mat4 lightView = glm::lookAt(lightPosition, glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
glm::mat4 lightSpaceMatrix = lightProjection * lightView;
::glViewport(0, 0, static_cast<GLsizei>(window.getSize().x), static_cast<GLsizei>(window.getSize().y));
// first render pass - shadow mapping
framebuffer->bind();
::glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
::glClear(GL_DEPTH_BUFFER_BIT);
framebuffer->clearBuffer(static_cast<gl::GLenum>(GL_DEPTH), 0, glm::vec4(1.0f));
glEnable(GL_DEPTH_TEST);
// cull front faces to prevent peter panning the generated shadow map
glCullFace(GL_FRONT);
shadowMappingPipeline->use();
shadowMappingLightSpaceUniform->set(lightSpaceMatrix);
shadowMappingModelTransformationUniform->set(chickenModel->getTransformation());
chickenModel->draw();
shadowMappingModelTransformationUniform->set(quadModel->getTransformation());
quadModel->draw();
framebuffer->unbind();
shadowMappingPipeline->release();
glCullFace(GL_BACK);
// second pass - switch to normal shader and render picture with depth information to the viewport
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shadowRenderingPipeline->use();
shadowRenderingLightPositionUniform->set(lightPosition);
shadowRenderingLightColorUniform->set(glm::vec3(1.0, 1.0, 1.0));
shadowRenderingCameraPositionUniform->set(cameraPos);
shadowRenderingProjectionTransformationUniform->set(cameraProjection);
shadowRenderingViewTransformationUniform->set(cameraView);
shadowRenderingLightSpaceMatrixUniform->set(lightSpaceMatrix);
// draw chicken
shadowMapTexture->bind();
shadowRenderingModelTransformationUniform->set(chickenModel->getTransformation());
chickenModel->draw();
shadowRenderingModelTransformationUniform->set(quadModel->getTransformation());
defaultTexture->bind();
quadModel->draw();
defaultTexture->unbind();
shadowMapTexture->unbind();
shadowRenderingPipeline->release();
// (omitted) render the debugging quad with depth (shadow) map
window.display();
As shameful as it might be, the issue was with the wrong texture being bound.
The globjects library that I use to have few nice(-r) abstractions over OpenGL actually does not provide a smart logic around texture binding (as I blindly assumed). So using just Texture::bind() and Texture::unbind() won't automagically keep track of how many textures have been bound and increment an index.
E.g. it does not behave (roughly) like this:
static int boundTextureIndex = -1;
void Texture::bind() {
glBindTexture(this->textureType, this->textureId);
glActivateTexture(GL_TEXTURE0 + (++boundTextureIndex));
}
void Texture::unbind() {
--boundTextureIndex;
}
So after changing the texture->bind() to texture->bindActive(0) followed by shaderProgram->setUniform("texture", 0), I finally got to the mouray effect and correct shadow mapping:
Full change is in this commit.
I have a deferred renderer which appears to work correctly, depth, colour and shading comes out correctly. However the position buffer is fine for orthographic, while the geometry appears 'inverted' (or depth disabled) when using a perspective projection.
I am getting the following buffer outputs for orthographic.
With the final 'shaded' image currently looking correct.
However when I am using a perspective projection I get the following buffers coming out...
And final image is fine, although I don't incorporate any position buffer information at the moment (N.B Only doing 'headlight' shading at the moment)
While the final image appears correct, the depth buffer appears to be ignored for my position buffer...(there is no glDisable(GL_DEPTH_TEST) in the code.
The depth and normal buffers looks ok to me, it's only the 'position' buffer which appears to be ignoring the depth? The render pipeline is exactly the same in for ortho and perspective with the only difference being the projection matrix.
I use glm::ortho, and glm::perspective and I calculate my near/far clipping distances on the fly based on the scene AABB. For orthographic my near/far is 1 & 11.4734 respectively, and for perspective it is 11.0875 & 22.5609... The width and height values are the same, fov is 45 for perspective projection.
I do have these calls before drawing any geometry...
glEnable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
Which I use for compositing different layers as part of the render pipeline.
Am I doing anything wrong here? or am I misunderstanding something?
Here are my shaders...
Vertex shader of gBuffer...
#version 430 core
layout (std140) uniform MatrixPV
{
mat4 P;
mat4 V;
};
layout(location = 0) in vec3 InPoint;
layout(location = 1) in vec3 InNormal;
layout(location = 2) in vec2 InUV;
uniform mat4 M;
out vec4 Position;
out vec3 Normal;
out vec2 UV;
void main()
{
mat4 VM = V * M;
gl_Position = P * VM * vec4(InPoint, 1.0);
Position = P * VM * vec4(InPoint, 1.0);
Normal = mat3(M) * InNormal;
UV = InUV;
}
Fragment shader of gBuffer...
#version 430 core
layout(location = 0) out vec4 gBufferPicker;
layout(location = 1) out vec4 gBufferPosition;
layout(location = 2) out vec4 gBufferNormal;
layout(location = 3) out vec4 gBufferDiffuse;
in vec3 Normal;
in vec4 Position;
vec4 Diffuse();
uniform vec4 PickerColour;
void main()
{
gBufferPosition = Position;
gBufferNormal = vec4(Normal.xyz, 1.0);
gBufferPicker = PickerColour;
gBufferDiffuse = Diffuse();
}
And here is the 'second pass' shader to visualise the position buffer...
#version 430 core
uniform sampler2D debugBufferPosition;
in vec2 UV;
out vec4 frag;
void main()
{
vec3 val = texture(debugBufferPosition, UV).xyz;
frag = vec4(val.xyz, 1.0);
}
I haven't used the position buffer data yet, and I know I can reconstruct it without having to store them in another buffer, however the positions are useful for me for other reasons and I would like to know why they are coming out as they are for perspective?
What you actually write in the position buffer is the clip space coordinate
Position = P * VM * vec4(InPoint, 1.0);
The clip space coordinate is a Homogeneous coordinates and transformed to the normaliced device cooridnate (which is a Cartesian coordinate by a Perspective divide.
ndc = gl_Position.xyz / gl_Position.w;
At orthographic projection the w component is 1, but at perspective projection, the w component contains a value which depends on the z component (depth) of the (cartesian ) view space coordinate.
I recommend to store the normalized device coordinate to the position buffer, rather than the clip space coordinate. e.g.:
gBufferPosition = vec4(Position.xyz / Position.w, 1.0);
I have an OpenGL 3.3 program whichts has different objects in, for example a simple cube. The cube's dimensions are 1x1x1 (vertices from -0.5, -0.5, -0.5 to 0.5, 0.5, 0.5) and is textured with one 2D texture on each side. The texture is repeatable (seamless).
With my actual code the model scaling looks like this (ignore the actual texture):
After scaling like this:
In this case the texture in should stay at size in z-direction but repeate over the z-axis.
Is there a good way to scale the texture properly to the model's scaling to prevent it from stretching? Or do I have to create a 3D texture?
The problem i found is that in my shader I get only the (scaled) point of the cube, for example -0.5, -1,5, -0.5 but the texture's coordinates are only 2D (0.0, 0.0) and I don't know which side of the texture I have to scale since I don't know which side it will currently be rendered on.
For for the sake of completeness, however, the vertex shader code:
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
layout (location = 2) in vec2 aTexCoord;
out vec2 TexCoord;
out vec3 FragPos;
out vec3 Normal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
FragPos = vec3(model * vec4(aPos, 1.0));
Normal = mat3(transpose(inverse(model))) * aNormal;
TexCoord = aTexCoord;
gl_Position = projection * view * model * vec4(aPos, 1.0);
//gl_Position = projection * view * model * vec4(aPos, 1.0f);
//TexCoord = aTexCoord;
}
The fragment shader looks like this:
out vec4 FragColor;
in vec2 TexCoord;
// texture samplers
uniform sampler2D texture_diffuse1;
uniform vec4 color;
void main()
{
FragColor = color + texture(texture_diffuse1, TexCoord);
}
I'm a new opengl programmer. I am plotting a height map composed of thousands of triangles in a 3D graph format. They are scaled so that they are plotted between -1 and +1 in the three axis. Now I am able to zoom in the X axis only and am able to translate in the X axis as well by applying the appropriate scale and translation matrices. This effectively allows me to zoom right into the data and move it in the x direction as I choose.
The problem is, once I zoom, the data in the x direction now extends outside the -1 to + 1 region which the boundaries of a graph. I want this data to not be shown.
How is this done in modern OpenGL?
Thank you
Edit:
The matrices are as follows:
plottingProgram["projection_matrix"].SetValue(Matrix4.CreatePerspectiveFieldOfView(0.45f, (float)width / height, 0.1f, 1000f));
plottingProgram["view_matrix"].SetValue(Matrix4.LookAt(new Vector3(0, 0, 10), Vector3.Zero, new Vector3(0, 1, 0)));
and the vertex shader is
public static string VertexShader = #"
#version 130
in vec3 vertexPosition;
out vec2 textureCoordinate;
uniform mat4 projection_matrix;
uniform mat4 view_matrix;
uniform mat4 model_matrix;
void main(void)
{
textureCoordinate = vertexPosition.xy;
gl_Position = projection_matrix * view_matrix * model_matrix * vec4(vertexPosition, 1);
}
";
Here is a link to the graph:
http://va2fsq.com/wp-content/uploads/graph.jpg
Thanks
I solved this. After trying many things like glScissor, I happened upon the glClip_distance. So my initial try placed a Uniform in the shader which was set to
in vec3 vertexPosition;
uniform vec4 plane0 = (-1,0,0,1);
uniform vec4 plane1 = (1,0,0,1);
void main(void)
{
gl_ClipDistance[0] = dot(vec4(vertexPosition,1), plane0;
gl_ClipDistance[1] = dot(vec4(vertexPosition,1), plane2;
Now the problem with this is that the vec4 planes are scaled and translated by any model matrix scaling or transformations. So that wouldn't work. So the solution is to move the clip vectors outside of the vertex shader and apply the opposite scaling to them as follows:
Vector4 clip1 = new Vector4(-1, 0, 0, 1.0f / scale);
Vector4 clip2 = new Vector4(1, 0, 0, 1.0f / scale);
plottingProgram["model_matrix"].SetValue(Matrix4.CreateScaling(new Vector3(scale,1,1)) * Matrix4.CreateTranslation(new Vector3(0,0,0)) *Matrix4.CreateRotationY(yangle) * Matrix4.CreateRotationX(xangle));
plottingProgram["plane0"].SetValue(clip1);
plottingProgram["plane1"].SetValue(clip2);
and the complete vertex shader is given by
public static string VertexShader = #"
#version 130
in vec3 vertexPosition;
out vec2 textureCoordinate;
uniform mat4 projection_matrix;
uniform mat4 view_matrix;
uniform mat4 model_matrix;
uniform vec4 plane0;
uniform vec4 plane1;
void main(void)
{
textureCoordinate = vertexPosition.xy;
gl_ClipDistance[0] = dot(vec4(vertexPosition,1), plane0);
gl_ClipDistance[1] = dot(vec4(vertexPosition,1), plane1);
gl_Position = projection_matrix * view_matrix * model_matrix * vec4(vertexPosition, 1);
}
";
You can also translate in the same way.
I have been trying to implement a heightmap to my terrain shader, but the terrain remains flat. The texture is properly loaded in the vertex shader, and I try to use the greyscale values of the texture based on the mesh's uvs to adjust the vertex height:
//DIFFUSE VERTEX SHADER
#version 330
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform mat4 modelMatrix;
in vec3 vertex;
in vec3 normal;
in vec2 uv;
uniform sampler2D heightmap;
out vec2 texCoord;
void main( void ){
vec3 _vertex = vertex;
_vertex.y = texture(heightmap, uv).r * 2.f;
gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4(_vertex, 1.f);
texCoord = uv;
}
Fragment: (the splatmap works so ignore that)
uniform sampler2D splatmap;
uniform sampler2D diffuse1;
uniform sampler2D diffuse2;
uniform sampler2D diffuse3;
uniform sampler2D diffuse4;
in vec2 texCoord;
out vec4 fragment_color;
void main( void ) {
///Loading the splatmap and the diffuse textures
vec4 splatTexture = texture2D(splatmap, texCoord);
vec4 diffuseTexture1 = texture2D(diffuse1, texCoord);
vec4 diffuseTexture2 = texture2D(diffuse2, texCoord);
vec4 diffuseTexture3 = texture2D(diffuse3, texCoord);
vec4 diffuseTexture4 = texture2D(diffuse4, texCoord);
//Interpolate between the different textures using the splatmap's rgb values (works)
diffuseTexture1 *= splatTexture.r;
diffuseTexture2 = mix (diffuseTexture1, diffuseTexture2, splatTexture.g);
diffuseTexture3 = mix (diffuseTexture2,diffuseTexture3, splatTexture.b);
vec4 outcolor = mix (diffuseTexture3, diffuseTexture4, splatTexture.a);
fragment_color = outcolor;
}
Some additional info:
All textures are loaded like this in my terrain material and passed to the shader (works properly):
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, heightMap->getId());
glUniform1i (_shader->getUniformLocation("heightMap"),0);
...
The plane mesh uvs are mapped like this:
(0,1) (1,1)
(0,0) (1,0)
I guess I am doing something horribly wrong, but I can't figure out what. Any help is appreciated!
Does your writing this:
The plane mesh uvs are mapped like this:
(0,1) (1,1)
(0,0) (1,0)
… mean that your mesh consists of just 4 vertices? If so, then that's your problem right there: The Vertex shader can not magically create "new" vertices, so your heightmap texture is sampled at only 4 points (and nothing in between).
And because you sample the texture coordinates at integer values and your texture coordinates and are at 0 and 1, you're effectively sampling the very same texture coordinate, so you're going to see the same displacement for all four vertices.
Solution: Tesselate your base mesh so that there are actually vertices available to displace. A tesselation shader is perfectly fine for that.
EDIT:
BTW, you can simplyfiy your vertex shader a bit: For the attributes make it a
in vec2 vertex;
which requires just 2/3 of the space of vec3, since you're not using the z component anyway.
float y = texture(heightmap, uv).r * 2.f;
gl_Position =
projectionMatrix
* viewMatrix
* modelMatrix
* vec4(vertex.x, y, vertex.y, 1.f);