Please help translating projection matrix for blur

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1

Hey, thanks for this awesome library and I apologize in advance for the following dumb question. In several places ImGui docs recommend trying a translation of the projection matrix by 0.5f, 0.5f or 0.375, 0.375. Could someone help me do that in the context of this binding for emscripten/SDL?

Here’s what seems to be the relevant code from that binding’s render function:

// Setup viewport, orthographic projection matrix
glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
const float ortho_projection[4][4] =
{
{ 2.0f/io.DisplaySize.x, 0.0f, 0.0f, 0.0f },
{ 0.0f, 2.0f/-io.DisplaySize.y, 0.0f, 0.0f },
{ 0.0f, 0.0f, -1.0f, 0.0f },
{-1.0f, 1.0f, 0.0f, 1.0f },
};
glUseProgram(g_ShaderHandle);
glUniform1i(g_AttribLocationTex, 0);
glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);

Thanks!

2

Hi, although I won’t be able to help you with your specific question, just wanted to point out that the referenced repo is outdated and instead you might want to consider using the Emscripten example provided in Dear ImGui.