Mike Ash has written some microbenchmarks to test the speed of operations like Objective-C message dispatch and object creation, in response to people’s premature optimizations based on unfound assumptions. This is one of those issues that comes up rather often. The numbers are interesting – especially the Objective-C message send vs. floating point division – but I wanted some numbers for PowerPC, since ABI and hardware differences could be expected to reorder the list somewhat.
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Performance Comparisons of Common Operations, PPC Edition
Posted in Cocoa, Code
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GLSL uniform bindings for Cocoa
Executive summary: This article demonstrates the use of Objective-C’s dynamic object model and the Foundation framework to extract attributes from objects using information not available at compile time. This is done on the context of implementing OpenGL Shader Language support in a cross-platform game.
Introduction
A major feature of the current development line of Oolite is support for GLSL shaders. Shaders need to be able to reflect the state of the object they’re attached to – for instance, by having spaceship engines glow in proportion to engine power. The mechanism GLSL provides for this is uniform variables, attributes set by the host application and read by the shader.
Debris model with per-pixel lighting and heat glow which fades over time from glow_alloy.oxp. Model by Arexack_Heretic, textures by Griff, shaders by Ahruman.
Posted in Cocoa, Oolite, OpenGL
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