0
votes
1answer
27 views

OpenGL strange rendering problem when buffers have different sizes

I have encountered a very odd error in my program, "odd" in the sense that everything the API says suggests that the error should not occur. I have a bunch of 2D un-indexed vertex data, and I want to ...
0
votes
1answer
136 views

What is “ping pong” in the context of graphics rendering?

I have to render a scene, once per light, and blend the result of the various passes. I heard and read that one way to increase performances and render targets to use would be ping pong. I'm new to ...
4
votes
1answer
116 views

cost of texture change vs color change

How would I go about determining the difference in cost between changing the render color of an object every frame vice changing the texture (same sheet, just changing the source rectangle) every ...
2
votes
2answers
104 views

Render with multiple lights (one pass per light)

I have already a system that at the moment handle multiple lights just passing an array of light struct and loop through it. I had been told to switch to a multipass rendering approach. How should I ...
0
votes
1answer
34 views

When and how to apply affine translations to vertices of a mesh with LWJGL

So, I have a rigid body class, containing a list of vertices and a 4x4 transformation matrix. At the moment, I'm applying the transformation matrix to each vertex individually, and am unable to revert ...
0
votes
0answers
32 views

OpenGL - using gluSphere

I have an OpenGL code that currently draws several spheres at different locations. I generate the vertex buffer data (and normal data) myself. However, to simplify the code and increase efficiency, I ...
0
votes
1answer
40 views

Render on other render targets starting from one already rendered on

I have to perform a double pass convolution on a texture that is actually the color attachment of another render target, and store it in the color attachment of ANOTHER render target. This must be ...
10
votes
1answer
281 views

Rendering only a part of the screen in high detail

If graphics are rendered for a large viewing angle (e.g. a very large TV or a VR headset), the viewer can't actually focus on the entire image, just a part of it. (Actually, this is the case for ...
0
votes
0answers
56 views

Libgdx - 2D Mesh rendering overlap glitch

I am trying to render a 2D circle segment mesh (quarter circle)using Libgdx/Opengl ES 2.0 but I seem to be getting an overlapping issue as seen in the picture attached. I cant seem to find the cause ...
1
vote
1answer
31 views

How should I handle a modelview stack with multiple shader programs involved?

I'm building a framework where each object has an associated program and each object has a 'draw' method. What is the best choice, to have a single modelview stack handled by a Renderer class or to ...
1
vote
0answers
99 views

How can I reduce draw calls when using glBufferSubData and DYNAMIC_DRAW?

At first I had the problem where I had about 150 rectangles rendered every tick. I only used STATIC_DRAW and glBufferData. I added support for DYNAMIC_DRAW and glBufferSubData and now I have a very ...
1
vote
1answer
130 views

What should I do when a VBO becomes too large in OpenGL?

Currently I have one buffer for my vertex data and one buffer for normals data. I fill them and then pass them to OpenGL for rendering. The problem is when I load too large mesh file like "Lucy" from ...
0
votes
0answers
57 views

Diffuse Mapping in a Game

I want to figure out the diffuse maps of some rusted objects that I plan to render in my game arena. I have taken the images of some sample objects and have also scanned them for a model of the ...
12
votes
6answers
582 views

Seamless tilemap rendering (borderless adjacent images)

I have a 2D game engine that draws tilemaps by drawing tiles from a tileset image. Because by default OpenGL can only wrap the entire texture (GL_REPEAT), and not just part of it, each tile is split ...
2
votes
1answer
92 views

How do I check why is no output on screen?

I'm using OpenGL 3.3+, and I'm trying to create an orthographic projection to draw on screen. I have the model data in a buffer: X Y 0, 0 50, 100 100, 0 And I create my Model-View-Projection ...
3
votes
2answers
135 views

OpenGL - Index buffers problem

I have a custom file format that has all the needed information for a 3D mesh (exported from 3ds Max). I've extracted the data for vertices, vertex indices and normals. I pass to OpenGL the vertex ...
2
votes
4answers
325 views

Why would you use software rendering over hardware rendering, today?

As opposed to CPU or software rendering I assume? Wouldn't generally all current rendering be GPU based, seeing as you would be using OpenGL or Direct X? Could someone give me some info here, can't ...
0
votes
1answer
154 views

OpenGL: How to improve the performance of rendering context [closed]

I have written a benchmark program that compares the performance of OpenGL and DirectX libraries. The problem is that OpenGL gets much lower performance than Direct3D. At the end the program generates ...
0
votes
1answer
95 views

Correct GL settings to mix 2D and 3D rendering

I'm programming a 3D game engine with 2D GUI. The GUI objects have partially transparent textures and the transparency works more or less. The sky color is rendered in transparent areas of the ...
2
votes
2answers
145 views

How can I determine the pixels covered by a transformed triangle (without drawing it)?

I have three points that form a triangle in a 3D scene. I want to apply an arbitrary rotation/translation transformation to this polygon and later check in which pixels of an image they would be ...
7
votes
3answers
320 views

Terrain & Multi-Texturing

I'm using OpenGL (Version 4.4) (and C++ if that matters). I've created a terrain renderer, the terrain is stored as a 3D scalar field (isosurface/voxels). It uses a slightly modified version of ...
6
votes
1answer
226 views

With what projection matrix should I render a portal to a texture?

I'm using OpenGL. I have problem with my engine's portal implementation. To create the first portal I do: create a virtual camera with the position of the second portal and the correct orientation ...
2
votes
3answers
172 views

Order of render with transparency opengl

I tried to render using different render configurations (GL_BLEND_FUNC()) but I couldn't get the back object to render in certain angles. The first screenshot here shows one angle where the back ...
0
votes
1answer
109 views

Keep rasterized pixel amount constant

I have a scene that is rendered from the point of view of the light using an orthographic projection matrix. For an arbitrarily shaped and oriented object that doesn't change its shape or size in ...
1
vote
1answer
107 views

opengl offscreen rendering in linux is slow [duplicate]

My opengl application runs at about 110 fps. The moment I add off-screen rendering, it slows down to 15 fps. I am using frame buffer objects and glReadPixels to render off-screen. I have searched on ...
0
votes
2answers
157 views

Models are not rendered correctly. OpenGL

I'm working on my university OpenGL project and as a base of it I'm trying to combine several OpenGL tutorials, mainly tutorials from http://ogldev.atspace.co.uk/. The problem I have is that models ...
0
votes
2answers
217 views

How forward rendering done using OpenGL?

Recently I come across the term forward rendering. I'm kind of curious how this could be done in OpenGL. I have done a lot of search on this, majority of the result I get are on theory but not code ...
0
votes
1answer
167 views

Why am I seeing undesirable rendering results using VBOs like this?

I am trying to write a program that renders using VBO(vertex buffer objects). Everything works great except that when I run the program, It looks like the object is spazzing out. I think its due to ...
1
vote
1answer
41 views

Drawing behavior when a fragment is written to multiple times in a single pass

This seems really basic, but I'm confused and can't find a clear answer anywhere. What happens to a target fragment of a rendertarget if the fragment is written to multiple times within one pass ...
0
votes
2answers
207 views

Batching elements

I don't understand exactly how batching works. What I have understood: Batching is useful to regroup similar elements together and draw them in one draw call (performance++), currently drawing an ...
4
votes
2answers
432 views

What Shading/Rendering techniques are being used in this image?

My previous question wasn't clear enough. From a rendering point of view what kind of techniques are used in this image as I would like to apply a similar style (I'm using OpenGL if that matters): ...
2
votes
3answers
542 views

Visitor-pattern vs inheritance for rendering

I have a game engine that currently uses inheritance to provide a generic interface to do rendering: class renderable { public: void render(); }; Each class calls the gl_* functions itself, ...
2
votes
1answer
226 views

Material, Pass, Technique and shaders

I'm trying to make a clean and advanced Material class for the rendering of my game, here is my architecture: class Material { void sendToShader() { program->sendUniform( ...
17
votes
6answers
2k views

Separating game data/logic from rendering

I'm writing a game using C++ and OpenGL 2.1. I was thinking how could I separate the data/logic from rendering. At the moment I use a base class 'Renderable' that gives a pure virtual method to ...
0
votes
1answer
368 views

Texture Won't Load in OpenGL

I've started trying to make a 2D game in C++ using OpenGL, and I'm using SOIL as the imaging loading library. The problem is, I've been trying to get a simple 64x64 image of a red square to open and ...
0
votes
1answer
158 views

OpenGLES 2.0 batching method and do not draw inactive object

I am researching about "batching" objects for one big VBO and reduce draw call. These are what I am doing now: Create interleaved VBO based on texture or render state (like Blending) So, for ...
-2
votes
2answers
127 views

In OpenGL, how to confirm a primitive is rendered properly

I have to confirm that a primitive (say triangle) is rendered properly in opengl. I can use the glGetError() after a opengl draw calls(glDrawElement/glDrawArrays) Is it enough to confirm ? Is there ...
2
votes
0answers
83 views

How do I calculate the points of a brush from a Source engine VMF? [closed]

I'm trying to render the brushes from a Source engine .vmf file in C++, using OpenGL. The .vmf stores solid brushes as a series of planes which I would like to use to calculate the points for each ...
-3
votes
1answer
346 views

OS X OpenGL 3.2 Core (Black Screen)

I want to render a Quad via VAO, IBO and VBO but nothing is drawn. I'm using glDrawRangeElements in OS X OpenGL 3.2 Core context. The screen is completely black without any error. GLFW3 is used to ...
3
votes
1answer
87 views

Texturing a quad

Drawing a quad with a texture mapped to it with the fixed OpenGL pipeline is one of the easiest things to do in OpenGL. And for some madmaking, mysterious, dumb reason I can't get it to work. I ...
0
votes
3answers
329 views

Using different shaders on the same model at runtime

I've already asked similar but a bit unclear question here but this time I will be very specific and to the point. Suppose I have an actor which grabs a power up. He starts to glow using bloom shader ...
0
votes
1answer
680 views

Why won't my vertex buffer render in GLFW3?

I have started to try to learn OpenGL, and I decided to use GLFW to assist in window creation. The problem is, since GLFW3 is so new, there are no tutorials on it or how to use it with modern OpenGL ...
-2
votes
2answers
176 views

Rendering structure [closed]

my question is "What is the best way to structure rendering code". Is it better to make a class with a render function that iterates through all game objects based on there name or type and have no ...
0
votes
1answer
306 views

Drawing the same scene with perspective then orthographic projections

I have a scene that I'm rendering first with a perspective matrix. I then want to rerender it in a different viewport using an orthographic matrix for a top-down 2D view of the scene. I think I may be ...
1
vote
0answers
345 views

Optimal OpenGL 2D Sprite Batching (Best Practice)

I am working on simple 2D engine using OpenGL (3.3+) for rendering and was wondering what the optimal method of sprite batching would be. I plan to put all sprites into one (or fewer) texture atlases. ...
3
votes
1answer
216 views

Rendering a black and white image in OpenGL 1.1

Is there is any way that I can simple disable the color in OpenGL 1.1? Or can I "grey out" textures in LWJGL?
2
votes
1answer
306 views

Not repeating background in platformer [closed]

I need to make not repeating background for platformer. I can't find any description of implementation and I developed algorithm but I'm not sure that it's right. I can't load one big texture per ...
1
vote
1answer
276 views

Using two FBOs results in the second FBO having nothing drawn to [closed]

I'm writing a deferred renderer, and I use two FBOs: the first one for G-buffer (color, normal, depth) and the second one for lighting (light output), so the first one has three textures bound and the ...
0
votes
1answer
358 views

How to scale a texture in OpenGL/LWJGL?

How would I take a texture and render it to a specific size? The texture I'm rendering has a 1:1 ratio so I want to be able to render the whole image like if the window is wide then put black outlines ...
3
votes
1answer
431 views

How do I render a filled and stroked path using OpenGL?

I want to render a 2-dimensional geometric path consisting of Bézier curves and straight lines. Paths can be concave. What is the most efficient way to draw this using modern OpenGL? Can I do this ...