Deformable terrain in OpenGL 2D [Worms alike]

Question

I searched for a while, and I heard about different ways of doing this, so I thought that I would come here and see what I should do,

From what I put together, I have to use .. glBitmap and 0s and 0xFF values ​​in an array to make terrain. Any input on this? I tried switching it to ATVs, but I'm not sure if this is effective and the way it should have been done.

I want the terrain to have tunnels such as worms. size 2.

Here is what I have tried so far,

I tried to make glBitmap, so ..

pixels = pow(2 * radius, 2); ras = new GLubyte[pixels]; 

and then set all the values ​​to 0xFF and draw them using glBitmap (x, y, 0, 0, ras); Then it can be checked for explosions, and what not, and any pixels can be set to zero. Is this a plausible approach? I'm not too good with opengl, can I put the texture on glBitmap? From what I saw, I do not think you can.

Answer 1

I would suggest you use a stencil buffer. You mark the destroyed parts of the terrain in the stencil buffer, and then draw your terrain by testing the stencil with a simple ATV without manually testing each pixel.

Answer 2

OK, this is a high-level overview, and I assume that you are already familiar with the basics of OpenGL, such as buffer objects. Let me know if something doesn't make sense or if you want more information.

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The most common way to represent the landscape in computer graphics is the height field: a grid of points that are regularly located on the X and Y axes, but whose Z (height) can vary. The height field can have only one Z value for one (X, Y) grid point, so you cannot have “protrusions” on the ground, but in any case this is usually enough.

A simple way to draw a high-rise landscape is a triangular strip (or squares, but they are out of date). For simplicity, start at one corner and set the vertices in zig-zag order down the column, then return to the top and do the next column and so on. There are optimizations that can be performed to improve performance and more sophisticated ways to build geometry for a better look, but this will get you started.

(I am assuming rectangular terrain here, as this is usually done, if you really want a circle, you can replace 𝑟 and Θ with X and Y so that you have a polar grid.)

The coordinates for each vertex must be stored in the buffer object, as usual. When you call glBufferData() to load the vertex data into the GPU, specify either GL_STREAM_DRAW if the landscape will usually change from one frame to another, or GL_DYNAMIC_DRAW if it will change often but not (close to) every frame. To change the terrain, call glBufferData() again to copy another vertex dataset to the GPU.

For the vertex data itself, you can specify all three coordinates (X, Y, and Z) for each vertex; what is the simplest thing. Or, if you are using a fairly new version of GL and want to be complex, you should be able to calculate the X and Y coordinates in the vertex shader using gl_VertexID and grid sizes (passed to the shader as a uniform value). Thus, you only need to save the Z values ​​in the buffer, which means less GPU memory and bandwidth consumption.