ChobitsTheZero

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About ChobitsTheZero

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    Programming
  1. RayCasting - sphere, plane and OBB

    I have a problem understanding how excatly the intersection test when testing ray against plane, sphere and OBB. I have a presentation of an assignment and I need to be able to explain how the code I have written works. But I dont really understand it, even though I have searched over the internet and read through a lot of sites telling how it works. I still dont really understand it, im hoping that someone can give me a dummy explaination of it that is easy to understand. I'll provide the code in question down below, all help is appreciated. I just really wanna understand how this stuff works fully. void GiantSphere::test(Ray & ray, HitData & hit) { float b = ray.d.Dot(ray.o - this->center); float j = (ray.o - this->center).Dot(ray.o - this->center) - pow(this->radius,2); float intersectCalc = b*b - j; if (intersectCalc >= 0) { float t = -b - sqrt(intersectCalc); if (hit.t == -1 || hit.t > t) { hit.t = t; hit.lastShape = this; hit.color = this->c; hit.lastNormal = this->normal(ray.o+ray.d*t); } } } Vec GiantSphere::normal(Vec & point) { Vec temp = point - this->center; temp.Normalize(); return temp; } GiantSphere::GiantSphere(Vec _center, float _radius, Color _color) { this->center = _center; this->radius = _radius; this->c = _color; } void GiantPlane::test(Ray & ray, HitData & hit) { float d = this->n.Dot(this->point); float t = (d - this->n.Dot(ray.o)) / this->n.Dot(ray.d); if (t > 0.0001f) { if (hit.t == -1 || hit.t > t) { hit.t = t; hit.lastShape = this; hit.color = this->c; hit.lastNormal = this->n; } } } Vec GiantPlane::normal(Vec & point) { point = n; return point; } GiantPlane::GiantPlane(Vec normal, float _d, Color color) { this->n = normal; //this->d = _d; this->point = this->n*_d; this->c = color; } void GiantOBB::test(Ray & ray, HitData & hit) { float tMin = -INFINITY; float tMax = +INFINITY; Vec p = Bcenter - ray.o; // Bcenter is the center of the OBB. Ray.o is the origin of the ray. Vec arr[3] = { Bu,Bv,Bw }; // Direction/base vectors. (1,0,0), (0,1,0), (0,0,1) for (auto& i : arr) { float e = i.Dot(p); float f = i.Dot(ray.d); float q = -e - halfBu; // The distance between the center and each side. 100. float w = -e + halfBu; if (abs(f) > 1e-20f) { float t1 = ((e + halfBu) / f); float t2 = ((e - halfBu) / f); if (t1 > t2) { std::swap(t1, t2); } if (t1 > tMin) { tMin = t1; } if (t2 < tMax) { tMax = t2; } if (tMin > tMax) { return; } if (tMax < 0) { return; } } else if (q > 0 || w < 0) { return; } } if (tMin > 0) { if (hit.t == -1) { hit.t = tMin; hit.lastShape = this; hit.color = c; } else if (tMin < hit.t) { hit.t = tMin; hit.lastShape = this; hit.color = c; } } else if (tMax <= 0) { if (hit.t == -1) { hit.t = tMax; hit.lastShape = this; hit.color = c; } else if (tMax < hit.t) { hit.t = tMax; hit.lastShape = this; hit.color = c; } } } Vec GiantOBB::normal(Vec & point) { Vec arr[3] = { this->Bu,this->Bv,this->Bw }; float halfArr[3] = { this->halfBu,this->halfBv,this->halfBw }; Vec returnValue = Vec(); for (int i = 0; i < 3; i++) { Vec sPlus = this->Bcenter + (arr[i] * halfArr[i]); Vec sMinus = this->Bcenter - (arr[i] * halfArr[i]); if ((point - sPlus).Dot(arr[i]) < 0.0001f && (point - sPlus).Dot(arr[i]) > -0.0001f) { float dot = (point - sPlus).Dot(arr[i]); returnValue = arr[i]; } else if ((point - sMinus).Dot(arr[i] * -1) < 0.0001f && (point - sMinus).Dot(arr[i] * -1) > -0.0001f) { float dot2 = (point - sMinus).Dot(arr[i]); returnValue = arr[i] * -1; } } return returnValue; } GiantOBB::GiantOBB(Vec b, Vec b1, Vec b2, Vec b3, float Hu, float Hv, float Hw, Color _color) { this->Bcenter = b; this->Bu = b1; this->Bv = b2; this->Bw = b3; this->c = _color; this->halfBu = Hu; this->halfBv = Hv; this->halfBw = Hw; } GiantOBB::GiantOBB(Vec b, float Hu, float Hv, float Hw, Color _color) { this->Bcenter = b; this->halfBu = Hu; this->halfBv = Hv; this->halfBw = Hw; this->c = _color; }
  2. OpenGL Shadowmapping issue - Shadows not showing

    Okey so, I did what you said but it seems that there is also another problem which I can't really figure out what it is. So now there are shadows, but they dont seem to be at the correct position. Instead of being behind the models they are instead infront of them and slightly above them. I was thinking that maybe I had to multiple the vec4(vertexPos, 1) with model, but that also gave a weird result. #Edit: Nevermind I was able to solve it, appearantly the lightspacematrix had some issues with it.
  3. OpenGL Shadowmapping issue - Shadows not showing

    I see! That really helps! I have kinda been short on time and really stressed due to exams so I basically has to rush through it all. But I shouldn't try to make excuses, I guess i'm just bad at understanding how excatly 3D programming works.
  4. I have been trying to implement shadows with the use of Shadowmapping in OpenGL. I sorta followed this tutorial https://learnopengl.com/#Advanced-Lighting/Shadows/Shadow-Mapping I have implemented the depthmap and have gotten it to render the depthmap. The problem I am having is when implementing the shadows. Now since this is part of a bigger project that uses Deferred Rendering, the code does not match the code in the tutorial but I am using the same concept. LightVertex shader:   #version 440 layout (location = 0) in vec3 vertexPos; layout (location = 1) in vec2 texCoords; out vec2 TexCoords; out vec4 FragPosLightSpace; uniform mat4 model; uniform sampler2D gPosition; uniform mat4 lightSpaceMatrix; void main() { gl_Position = vec4(vertexPos, 1.0f); TexCoords = texCoords; vec3 FragmentPos = vec3(model * texture(gPosition, texCoords)); FragPosLightSpace = lightSpaceMatrix * vec4(FragmentPos, 1.0); } LightFragment shader: #version 440 out vec4 FragColor; in vec2 TexCoords; in vec4 FragPosLightSpace; uniform sampler2D gPosition; uniform sampler2D gNormal; uniform sampler2D gAlbedoSpec; uniform sampler2D depthMap; struct Light { vec3 Position; vec3 Color; float Linear; float Quadratic; }; const int NR_LIGHTS = 32; uniform Light lights[NR_LIGHTS]; uniform vec3 viewPos; float ShadowCalculation(vec4 fragPosLightSpace) { //Perform perspective divide vec3 projCoords = fragPosLightSpace.xyz / fragPosLightSpace.w; //Transform to [0,1] range projCoords = projCoords * 0.5 + 0.5; //Get closest depth value from light's perspective (using [0,1] range fragPosLight as coords) float closestDepth = texture(depthMap, projCoords.xy).r; //Get depth of current fragment from light's perspective float currentDepth = projCoords.z; //Check wheter current frag pos is in shadow float shadow = 0.0; if(currentDepth > closestDepth) { shadow = 1.0; } return shadow; } void main() { // Retrieve data from G-buffer vec3 FragPos = texture(gPosition, TexCoords).rgb; vec3 Normal = texture(gNormal, TexCoords).rgb; vec3 color = texture(gAlbedoSpec, TexCoords).rgb; float Specular = texture(gAlbedoSpec, TexCoords).a; float shadow = ShadowCalculation(FragPosLightSpace); vec3 lighting = vec3(0.1 + (1.0-shadow),0.1 + (1.0-shadow),0.1 + (1.0-shadow)); vec3 viewDir = normalize(viewPos - FragPos); for(int i = 0; i < NR_LIGHTS; ++i) { vec3 lightDir = normalize(lights[i].Position - FragPos); vec3 diffuse = max(dot(Normal, lightDir), 0.0) * color * lights[i].Color; // Specular vec3 halfwayDir = normalize(lightDir + viewDir); float spec = pow(max(dot(Normal, halfwayDir), 0.0), 16.0); vec3 specular = lights[i].Color * spec * Specular; // Attenuation float distance = length(lights[i].Position - FragPos); float attenuation = 1.0 / (1.0 + lights[i].Linear * distance + lights[i].Quadratic * distance * distance); diffuse *= attenuation; specular *= attenuation; lighting += diffuse + specular; } lighting * color; FragColor = vec4(lighting, 1.0f); float depthValue = texture(depthMap,TexCoords).r; // Test depthmap //FragColor = vec4(vec3(depthValue),1.0); } The ShadowCalculation is the function that calculates if a position is in shadows or not. And it pretty much follows the same concept as the tutorial does. Now if I run all this, all I get is a white screen, I thought it might be because I had the setting of shadow wrong so I tried setting float shadow = 1.0 and then in the if-statement setting shadows to 0.0. Now I dont get a completly white screen but the shadows are not showing. I feel like I am close to a solution but have kinda gotten stuck right now and would appreciate if someone could tell me what the problem is or could be.
  5. Heightmap finding closest vertices

      How would I determine which triangle of the quad the camera is in?
  6. So I have rendered a terrain based on a heightmap. It's based on this tutorial that I followed - http://www.mbsoftworks.sk/index.php?page=tutorials&series=1&tutorial=8   Now I want to have my camera to be able to "walk" on the terrain. The getY() function gets the x and z coordinates of the camera, and I understand that with those I have to find the closest vertices of the terrain to decide which triangle the camera is over. The thing is i'm unsure of how to actually do that, I have looked for a lot of examples on google but haven't been able to find any concrete answers for it. Currently my code looks like this: HM_SIZE_X and HM_SIZE_Y are both 6       float Terrain::getY(int x, int z)     {          //return     }          void Terrain::createTerrain()     {     glClearColor(0.0f, 0.0f, 0.0f, 1.0f);          // Setup heightmap          glGenVertexArrays(1, &uiVAOHeightmap); // Create one VAO     glGenBuffers(1, &uiVBOHeightmapData); // One VBO for data     glGenBuffers(1, &uiVBOIndices); // And finally one VBO for indices          glBindVertexArray(uiVAOHeightmap);     glBindBuffer(GL_ARRAY_BUFFER, uiVBOHeightmapData);          float fHeights[HM_SIZE_X*HM_SIZE_Y] =     {     10.0f, 10.0f, 10.0f, 10.0f, 10.0f, 10.0f,     5.0f, 5.0f,5.0f, 10.0f, 10.0f, 10.0f,     5.0f, 5.0f, 5.0f, 10.0f, 10.0f, 10.0f,     5.0f, 5.0f, 10.0f, 10.0f, 10.0f, 10.0f,     10.0f, 10.0f, 10.0f, 10.0f, 10.0f, 10.0f,     10.0f, 5.0f, 5.0f, 5.0f, 5.0f, 10.0f,     };          float fSizeX = 100.0f, fSizeZ = 100.0f;          for (int i = 0; i<HM_SIZE_X*HM_SIZE_Y;i++)     {     for (int j = 0; j < HM_SIZE_X*HM_SIZE_Y; j++)     {     float column = float(i%HM_SIZE_X), row = float(i / HM_SIZE_X);     vHeightmapData[i] = glm::vec3(     -fSizeX / 2 + fSizeX*column / float(HM_SIZE_X - 1), // X Coordinate     fHeights[i], // Y Coordinate (it's height)     -fSizeZ / 2 + fSizeZ*row / float(HM_SIZE_Y - 1) // Z Coordinate     );     }     }          glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3)*HM_SIZE_X*HM_SIZE_Y, vHeightmapData, GL_STATIC_DRAW);     glEnableVertexAttribArray(0);     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);          glGenBuffers(1, &uiVBOIndices);     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, uiVBOIndices);     int iIndices[] =     {     0, 6, 1, 7, 2, 8, 3, 9, 4, 10, 5, 11, 36,     6, 12, 7, 13, 8, 14, 9, 15, 10, 16, 11, 17, 36,     12, 18, 13, 19, 14, 20, 15, 21, 16, 22, 17, 23, 36,     18, 24, 19, 25, 20, 26, 21, 27, 22, 28, 23, 29, 36,     24, 30, 25, 31, 26, 32, 27, 33, 28, 34, 29, 35     };     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(iIndices), iIndices, GL_STATIC_DRAW);     glEnable(GL_PRIMITIVE_RESTART);     glPrimitiveRestartIndex(HM_SIZE_X*HM_SIZE_Y);     }